More Weighings:
Exploring the Ploidy of Hybrid Elepidote Rhododendrons
Sally Perkins and John Perkins, Salem, New Hampshire
Mariana Castro, Jose Cerca De Oliveira, Silvia Castro, and Joao Loureiro Plant Ecology and Evolution Group, Centre for Functional
Ecology, Department of Life Sciences, Faculty of Science and Technology, University of Coimbra, Portugal
enthusiasts may not know it, but
R they love polyploid hybrid elepidotes. Check
any flower show bench and look at the finalists for
awards. Mention Rhododendron 'Cynthia, `Gomer
Waterer', 'Grace Seabrook', 'Horizon Monarch',
`Marinus Koster', 'Pink Pearl', 'Phyllis Korn,
`Point Defiance', 'Taurus', or 'Trude Webster', and
gardeners quickly declare these as among their
favorite rhododendrons or high on their wish list.
Yes, these rhododendrons all display "something
different" and are "highly desirable". They have
larger than normal levels of genetic material. They
are polyploids.
More than 80 rhododendrons with larger than
normal ploidy levels are revealed below. We hope
gardeners will see the connection of polyploidy to
characteristics of thickness in the stem, leaf, and leaf
petiole, along with firmness in flower substance.
Indeed, remarkable vigor and substance overall,
coupled with an outstanding floral performance at a
young age, are often associated with a higher ploidy
level. Even gardeners who never want to hear about
ploidy love talking about their polyploid hybrid
elepidote rhododendrons.
We (Sally and John Perkins) are not geneticists.
We do have science backgrounds, combined with
a passion for knowledge. Our ploidy journey
began as simple curiosity combined with a
willingness to coordinate with others, to scour the
Rhododendron literature and the Web, and to do
some field work, leading to more discoveries than
we ever imagined. Engaging the expertise of Joao
Loureiro and his research team from the University
of Coimbra, Portugal, transformed this journey.
We have continued this journey further, exploring
the interesting comments and conclusions from
28 • The Azalean / Spring/Summer 2015
multiple rhododendron breeders and enthusiasts. We
hope you will attempt to grow the newer polyploid
elepidotes, take up the challenge of hybridizing even
more, and take an interest in the history of their
development.
We keep a running list of possible higher ploidy
hybrids that could be worthwhile testing should we
find a source of samples for testing. These are parents,
siblings, or progeny of known polyploid hybrids, visually suspicious plants, or plants suggested by knowledgeable rhododendron people. Thankfully, at the
2011 American Rhododendron Society Conference
in Vancouver, Washington, Steve Hootman of the
Rhododendron Species Botanical Garden in Federal
Way, Washington, introduced us at the banquet table
to Hartwig Schepker. Hartwig gave a talk the following evening and as Scientific Director of the Botanic
Garden and Rhododendron-Park Bremen, Germany,
home of one of the largest Rhododendron collections
in the world, we immediately realized that here was
a person who had access to additional rare material.
Our ongoing polyploid journey would not have to
end with so many unanswered questions. Hartwig
also realized that this too could be the beginning of a
mutually beneficial relationship, and all he needed to
provide would be three floral buds per hybrid for flow
cytometry testing by the research team at Portugal's
University of Coimbra.
Background In Ploldy terms
When we refer to ploidy we mean the "size" of the
plant's genetic material. In seed-bearing plants, the
genetic material is found in the nucleus of the cell,
packed into structures called chromosomes. There are
two different techniques used to determine how much
genetic material is in a cell and therefore, an estimate
of the number of chromosomes that are present in
that cell. One can "count the ways" or "weigh the
counts".
Count the ways: The classic way to determine the
number of chromosomes in a plant is to "visualize"
the chromosomes with stain where they are actively
growing, as in a root tip, and then count the different
pairs under the microscope. Reports are that this is
very tedious (more so in rhododendrons), subject to
error, and even eager graduate students are reluctant
to cooperate. Chromosome counts are often not
duplicated and rarely use multiple specimens.
Weigh the counts: With flow cytometry, it is
possible to weigh the genetic material by taking
healthy plant tissue (such as leaf, flower or seed)
and measuring the "weight" of the genetic content.
This technique is much less time consuming and,
therefore, easier to verify by duplicating results.
Flow cytometry was developed to detect cancer
cell mutations in humans. If the cells are normal and
growing, a weighted value representing the normal
number of chromosomes would be dominant. There
also would be a small number of cells with double
the weight of their chromosomes, the ones in the
duplicated state, just prior to cell division. Any cells
with less than or more than either of those two weights
would be an indication of mutations of the amount
of genetic material in the cell (i.e. cancer). Flow
cytometry is used in this paper to detect the normal
weight of genetic material in different Rhododendron
species and elepidote hybrids.
Polyploidy: Beginning with 1, 2, 3, 4, and 5.
In most plant cells, i.e. leaves, stems, roots and
some parts of the flower, the chromosomes are paired
with a matching chromosome to form the diploid
state. We say most cells because when it comes time
to sexually reproduce, the gametes (cells that fuses
with other cells during fertilization) that are the
unfertilized seed and the pollen are formed by the
splitting apart of the paired chromosomes during a
process called meiosis. This forms a nucleus with a
single set of chromosomes, the unpaired or haploid
state. And just to make things complicated, "true
seeds" undergo double fertilization, so that they
have two haploid nuclei from the seed parent that
are fertilized with a haploid pollen nucleus to form
the endosperm of a seed. The fertilized endosperm
therefore has three sets of chromosomes (two from
the seed mother and one from the pollen father)
and is triploid. This triploid material nourishes the
germinating seedling's growth.
Most rhododendrons get one set of13 chromosomes,
denoted as lx, from each parent (female and male)
resulting in two sets of chromosomes. The diploids
formed in this manner are denoted as 2x (lx + lx = 2x
= 26 chromosomes). However, some rhododendrons
have four sets of chromosomes. These are commonly
referred to as tetraploids, and denoted as 4x (2x
+ 2x = 4x = 52 chromosomes). Triploids have
three sets of chromosomes and are denoted 3x.
Pentaploids have five sets of chromosomes and are
denoted 5x. Rhododendrons having more than two
sets of chromosomes are referred to as polyploid
rhododendrons (Ranney et al. 2008).
All species of elepidote rhododendrons that we
have tested have been confirmed to be diploid with
the noteworthy exception of R. decorum ssp. diaprepes
`Gargantua'. However, there is no evidence that the
subspecies diaprepes is tetraploid; only the named
form `Gargantua' (selected from seed raised from
Forrest 11958) has tested as tetraploid. To date, no
wild elepidote population has tested as tetraploid,
but this could change. We were hopeful and then
disappointed that two relatively new species with
stiff, thick leaves, R. platypodum and R. yuefengense,
both tested as typical diploids.
In very rare instances, a parent will not go through
the normal splitting process of meiosis and, as a result,
the gametes are unreduced. Unreduced gametes
donate the plant's full complement of chromosomes
to the fertilized embryo. We are very interested in
those rare occurrences. It is also possible to artificially
induce a higher ploidy with chemicals that interfere
with normal chromosome splitting. For example,
Augie Kehr in North Carolina was able to form a
tetraploid elepidote R. maximum 'Summer Joy' *
and a lepidote R. minus 'Epoch' using colchicine.
The terms neotetraploid or neopolyploid refer to a
recent hybrid, whether man-made or natural, that is
The Azalean / Summer/Spring 2015 • 29
a higher ploidy than the diploid state.
Although most rhododendron species are diploid,
stable populations of tetraploid Rhododendron species
do exist within deciduous azaleas and lepidotes (Zhou
et a1.2008). An individual triploid rhododendron can
occur naturally where diploid and tetraploid species
of Rhododendron are co-located, and they appear
to be hybrids (Perkins et al.09/2010). For example,
natural triploid deciduous azaleas exist in Audra State
Park in West Virginia, Hurricane Creek in Georgia,
and Wayah Bald in North Carolina.
Exploring: the Journey
In the fall of 1989, our Rhododendron polyploidy
journey unknowingly started when we overheard at a
local rhododendron meeting a statement that Frank
Mossman wrote in 1972 concerning his hybridization
efforts with Rhododendron occidentale:
"We have found that Rhododendron occidentale
will cross with many other rhododendrons
or azaleas if occidentale is the seed parent, but
occidentale as a pollen parent produces few
seed." (Mossman 1972).
We wondered, "Why?"
In the fall of 2011 we read in the ARS online ejournal
that in 1972 Harold Greer wrote the following
concerning his hybridization of 'Countess of Derby'
to produce 'Trude Webster':
"If you are one of those who feels that there
could be nothing outstanding produced in a
pink rhododendron I would have been the first
to agree with you. That was until I saw the first
bud unfold on the original seedling of 'Countess
of Derby' selfed" (Greer 1972).
Both Mossman and Greer had encountered the
wonder accompanying the many puzzles presented
by polyploid rhododendrons, so we were in good
company.
Starting in the early 1990s, we unknowingly crossed
deciduous azaleas involving different ploidy levels,
leading in 2010 to collecting samples of diploid,
triploid and tetraploid rhododendrons for ploidy
30 • The Azalean / Spring/Summer 2015
testing at the University of Coimbra in Portugal.
Each step on this pathway revealed more about the
wonderful world of ploidy in our own rhododendron
garden. Below is a summary of what we discovered,
often based on the research, observations, and
documentation of many others, about the ploidy
of hybrid elepidote rhododendrons and the people
encountered on our slow but wondrous journey.
Imagine if you will the following:
It is 1913 and a beautiful spring day in England,
so what do you do? George V is the first Windsor
King, Woodrow Wilson is serving his first term as
President of the United States, and World War I is
a future event. In bloom are the two most popular
rhododendrons in the world at that time, 'Pink Pearl',
an 1890s Waterer hybrid, and 'Cynthia', an 1850s
Standish & Noble hybrid. On a beautiful spring day
in 1913, if you were Henry 'Harry' White, a nursery
manager in Sunningdale, England, you would have
crossed 'Pink Pearl' with 'Cynthia', and later named a
seedling from this cross 'Countess of Derby'.
It is spring 1961; John Kennedy is the handsome
young President of the United States and Vietnam is a
country unknown to most Americans. On a beautiful
spring day in 1961, if you were Harold Greer, living
in Eugene, Oregon, you selfed 'Countess of Derby'
and later named a seedling from this cross 'Trude
Webster'.
It is spring 1969; Richard Nixon is now the
President of the United States, and Watergate is
simply an office building in the DC area. On a
beautiful spring day in 1969, if you were Robert
Korn in Renton, Washington, you placed the pollen
from `Gomer Waterer', a 1900 Waterer 'Pink Pearl'
hybrid, onto 'Diane' and later named a seedling from
this cross 'Phyllis Korn'.
It is spring 1988; George H. Bush is the Vice
President of the United States, and Iraq is simply a
country somewhere in the Middle East. On a beautiful
spring day in 1988 if you were Jim Barlup, living in
Bellevue, Washington, you crossed 'Whitney's Late
Peach' by 'Phyllis Korn'. You later named a seedling
from this cross 'Summer Peach'.
It is spring 2001, George W. Bush is the President
of the United States and the Twin Towers in New
York City are still standing. On a beautiful spring day
in 2001 if you were Jim Barlup, living in Bellevue,
Washington, you crossed 'Phyllis Korn' by 'Trude
Webster' to create several viable offspring. You later
named a seedling from this cross 'White Ginger'.
So what have you done by starting all
this in 1913?
Well, you took two fertile triploids from the
19th century, namely 'Pink Pearl' and 'Cynthia' and
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pentaploid seedlings and from these selected 'White
Ginger' (Fig. 1).
By doing so, you ended the myth that triploids
are always sterile and showed that triploids can, in
fact, be both seed and pollen parents. Moreover,
triploids, when used in hybridization, produce
mostly reduced but some unreduced gametes.
You demonstrated that triploids provide a pathway
for the bi-directional transfer of genes between
diploids, triploids, tetraploids, and pentaploids. It
took your imagination a few beautiful spring days
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Figure 1: GENERATIONAL BREEDING OF POLYPLOID HYBRID ELEPIDOTES demonstrating that triploids can be fertile
and can create a bi-directional pathway between ploidy levels.
created a tetraploid, namely 'Countess of Derby'.
You then selfed the tetraploid 'Countess of Derby'
creating another tetraploid, namely 'Trude Webster'.
You then placed pollen from the triploid `Gomer
Waterer' onto a diploid seed parent, namely 'Diane'
and created a triploid, namely 'Phyllis Korn'. You
then used the pollen of that triploid, 'Phyllis Korn'
and crossed it with Whitney's Late Peach' (untested
but probably a diploid) to create a diploid, namely
`Summer Peach'. You then placed the pollen of
the tetraploid 'Trude Webster' onto the triploid
seed parent 'Phyllis Korn and produced a series of
doing crosses, a few changes of names and addresses,
nearly 90 years, and a team of young researchers at
the University of Coimbra in Portugal to confirm
your results, but all in all not a bad piece of work!
The following ploidy list of named hybrid elepidote
Rhododendrons as determined using flow cytometry,
all by Joao Loureiro, Silvia Castro, Jose Cerca
Oliveira, and Mariana Castro, Plant Ecology and
Evolution Group, Centre for Functional Ecology,
Department of Life Sciences, Faculty of Science and
Technology, University of Coimbra, Portugal, unless
otherwise indicated.
The Azalean / Summer/Spring 2015 • 31
Summary of Ploidy
Key:
F indicates a fertile triploid.
T indicates a chemically induced tetraploid.
P indicates a diploid with a polyploid ancestor.
S indicates a diploid with a tetraploid parent.
U indicates a diploid with a tendency to produce
unreduced gametes.
DM indicates a triploid resulting from a triploid
parent.
NM indicates a triploid resulting from a tetraploid
parent.
UM indicates a triploid resulting from 2 diploid
parents.
2X4 or 4X2 indicates a tetraploid resulting from a
diploid and a tetraploid parent.
3X2 indicates a tetraploid resulting from a triploid
and a diploid parent.
3X3 indicates a tetraploid resulting from 2 triploids
parents.
3XQ indicates a tetraploid resulting from at least one
triploid parent.
4X4 indicates a tetraploid resulting from 2 tetraploid
parents.
4X3 indicates a tetraploid or pentaploid resulting
from a tetraploid and a triploid parent.
4XQ indicates a tetraploid or pentaploid resulting
from a tetraploid parent.
% indicates flow cytometry ploidy testing was done
by research team led by Tom %limey.
# indicates flow cytometry ploidy testing was done by
Tom EeckHaut.
(,) indicates the name of the hybridizer and date of
cross related to use or production of a polyploid.
* indicates not registered.
2x Diploids (89 Total, 22 from Polyploid Parents)
`1000 Butterflies'
Adriaan Koster'
Alice '
Anna' (Lem, 1952) U
`Bethany Jade'
`Betty Hume
`Bibiani'
`Bruns Sirius' (Bruns, 1955) P
32 • The Azalean / Spring/Summer 2015
`Cheyenne'
`Colonel Coen
`Countess of Athlone'
`Dagmar' (Kavka, 1965) P
`Diane
`Doctor H.C. Dresselhuys'
`Doctor V.H. Rutgers'
`Donald Waterer' (Waterer, 1916) P
`Don Juan'
`Double Besse'
`Duke Of York'
`Elegans'
`Everlasting' %
`Fantastica' %
`Furnivall's Daughter'
`George Hardy' (Mangles, 1884) U
`Gillii'
`Gill's Triumph'
`Goldflimmer' %
`Goldsworth Orange' #
`Gotham Rheingold'
`Graf Zeppelin (van Nes, 1934) P
`Gunborg' (Sagemuller, 1964) P
`Heinje's Venezia' (Sagemuller, 1964) P
`Horizon Lakeside'
`Hotei'
`Hurricane' (Whitney, 1960) P
`Irmelies' (Hachmann, 1962) P S
`Isabel Pierce'
Isadora' (Sagemuller, 1962) P
`Janet Blair' %
1.G. Millais' (Waterer, 1915) P
`Jingle Bells' #
`Kathe Heinje' (Heinje, 1964) P
`Kathy Van Veen'
`Kupferberg' #
`Lady Bligh'
`Lady de Rothschild'
`Lady Eleanor Cathcart'
`Lady Longman (White, 1929) P
`Lem's Cameo'
`Loderi Venus'
`Loder's White'
`Madame Carvalho'
`Maxecat' %
R. maximum `Kalamity'
R. maximum Delp's Red Max'
`Mindy's Love'
`Mother of Pearl' (Tink Pearl' sport, 1925) P
`Mrs A.T. de la Mare'
`Mrs E.C. Stirling' (Waterer, 1906) P
`Mrs Furnivall'
`Mrs Lindsay Smith'
`Nancy Evans'
`Naselle'
`Norman Gill'
`Nova Zembla' %
`Olin 0. Dobbs'
`Orange Leopard' (Brack, 1988) P S
`Peach Charm'
`Peach Recital' (Barlup, 1996) P
`Phipp's Yellow'
`Pink Prelude'
`Polar Bear' %
`Professor J.H. Zaaijer' (Endtz, 1958) P
`Puget Sound' %
`Red Olympia
`Rendezvous' (Hachmann, 1968) P S
`Scandinavia (Koster, 1950) P
`Shoreham
`Sir Robert Peel'
`Stony Brook' (Brack, 1988) P S
`Summer Peach' (Barlup, 1988) P
`Summer Wind' (Barlup, 1996) P
`The Honourable Jean Marie de Montague' (van
Nes, 1901) U
`Voluptuous'
`Vulcan' %
Vulcan's Flame' %
Wanna Bee'
`White Pearl' (syn `Halopeanum')
`Wild Affair'
3x Triploids (51 Total)
`Anita Gehnrich' (Gehnrich) UM
`Anna Rose Whitney' (Van Veen, 1954) F NM
`Annie E. Endtz' (Endtz, 1939) DM
`August Lamken (Hobbie, 1942)
`Beauty of Littleworth' (Mangles, 1884)
`Betty Wormald' (Koster, 1907) F
`Broughtonii' (Broughton, 1840) F
`Caruso' (Hachmann, 1990) NM
`Charis' (Hachmann, 1990) NM
`Cotton Candy' (Henny & Wennekamp, 1958) F
UM
`Cynthia (Standish & Noble, 1856) F
`Dame Nellie Melba (Loder, 1926)
`Denali' (Elliott, 1987) NM
`Django' (Hachmann, 1985)
`Ebony Pearl' (Tink Pearl' sport, 1966)
`El Camino' (Whitney, 1976) NM
`Frentano' (Hachmann, 1989) NM
`Gartendirektor Rieger' (Hobbie, 1947)
`Gomer Waterer' (Waterer, 1900) F DM
`Grace Seabrook' (Seabrook, 1965) UM
`Halfdan Lem' (Lem, 1967) UM
`Hallelujah' (Greer, 1958)
`Hank's Folly' (Schannen) NM
`Hollandia' (Endtz, 1938) DM
`Johnny Bender' (Seabrook, 1960) F UM
`Julia Caroline' (Brockenbrough, 1990) NM
`Lady of Spain' (Lofthouse, 1966) NM
`Lucky Strike' (Van Veen, 1958) NM
`Lydia (Greer, 1963) F NM
`Markeeta's Flame' (Markeeta, 1960) UM
`Markeeta's Prize' (Markeeta, 1970) UM
`Newcomb's Sweetheart' (Newcomb, 1968) NM
`Opal Thornton' (Thornton) NM
Tearce's American Beauty' (Pearce, 1930) F
`Phyllis Korn' (Korn, 1969) F DM
`Pink Pearl' (Waterer, 1892) F DM
`Platinum Pearl' (Greer, 1983) F NM
`Queen Mary' (Felix & Dijkhuis, 1950) DM
`Romilda' (Hachmann, 1990) NM
Rothenburg' (von Martin, 1944)
`Rwain' (Colombel, 1993) F NM
`Solidarity' (Schannen, 1969) F UM
`Souvenir de Doctor S. Endtz' (Endtz, 1924) DM
`Steredenn' (Colombel) NM
`Sugar Pink' (Greer, 1960) NM
`Super Dog' (Bones) NM *
`Taurus' (Mossman, 1962) F UM
Topsvoort Pearl' (Tink Pearl' sport, 1935)
`Val d'Aulnay' (Croux & Fils, 1984) F
The Azalean / Summer/Spring 2015 • 33
`Van' (Van Veen, 1930) NM
`Viscy' (Hobbie, 1950) UM
4x Tetraploids (31 Total)
Antoon van Welie' (Endtz, 1930) 3X2
Aristide Briand' (Endtz, 1950) 3XQ
`Brigg's Red Star' (Briggs) T
`Cherry Cheesecake' (Briggs) T % *
`Countess of Derby' (White, 1913) 3X3
R. diaprepes `Gargantua (Stevenson, 1923)
`Doctor A. Blok' (Endtz, 1937) 3XQ
`Doctor Arnold W. Endtz' (Endtz, 1927) 3XQ
`Doreen Gale' (Sanders) 4X4
`Friesland' (Endtz, 1958) 3XQ
`Gentle Giant' (Sanders, 1992) 4X3
`Germania' (Hobbie, 1956) 4X2
`Gorgeous George' (Sanders) 4X4
`Grand Slam (Greer, 1982) 4X3
`Horizon Jubilee' (Brockenbrough) % *
`Horizon Monarch' (Brockenbrough, 1981) 2X4
`Jan Dekens' (Endtz, 1940) 3XQ
`Le Fouesnantais' (Colombel, 1997) 4XQ
`Legend' (Barlup) 4X4
lem's Monarch' (Lem, 1965) 2X4
T.Engin' (de la Sabliere) 4X2 *
`Marinus Koster' (Koster, 1937)
`Pink Goliath' (van Nes, 1958) 4XQ
`Point Defiance' (Lem, 1970) 2X4
`Professor Hugo de Vries' (Endtz, 1958) 3X2
`Reverend Paul' (Sumner, 1975) 4X4
`Summer Joy' (Kehr) T *
`Supernova' (Briggs) T %
`Trude Webster' (Greer, 1960) 4x4
`Very Berry' (Greer, 1988) 4X2
`XXI: (ID'Flor) *
5x Pentaploids (2 Total)
`Haithabu' (Hachmann, 1991) 4XQ
`White Ginger' (Barlup, 2001) 4X3
Rhododendron oftheYear in 2006 by the Southwestern
Chapter of the American Rhododendron Society. In
1950, a large 'Cynthia, a triploid originally bred in
1858, was the first rhododendron planted in Portland
Chapter's Crystal Springs Rhododendron Garden.
`Trude Webster', a tetraploid, won the American
Rhododendron Society's first Superior Plant Award in
1971 and is still found on lists of Proven Performers
for the West Coast. 'Broughtonii', a triploid bred in
1840, is still considered to be among the best warm
weather rhododendrons according to Don Burke,
who gardens in Australia.
Historical evidence indicates that by 1910, the
triploids 'Betty Wormald', 'Beauty of Littleworth',
`Broughtonii', 'Cynthia', `Gomer Waterer' and 'Pink
Pearl' would have been on most lists of best elepidote
rhododendrons. In 1958, George Grace's list of
best elepidote rhododendrons included all but one
of these triploids plus the tetraploids 'Countess of
Derby' and `Marinus Koster'. In 2008, the Siuslaw
Chapter of the American Rhododendron Society
included on their list of best elepidote rhododendrons
the triploids 'Cynthia', 'Dame Nellie Melba', 'Grace
Seabrook', and 'Taurus', and the tetraploids 'Grand
Slam', lem's Monarch', Horizon Monarch', 'Point
Defiance' and 'Very Berry'.
By 2011, Rhododendrons of the Year, Proven
Performers, Awards of Garden Merit and Best in
Show trusses were added to the 'bests' mentioned
above, taking in the triploids 'Anita Gehnrich', 'Anna
Rose Whitney', 'Cotton Candy', 'Ebony Pearl',
`Gartendirektor Rieger', 'Hallelujah', `Markeeta's
Prize', 'Platinum Pearl', 'Solidarity' and 'Super
Dog', and the tetraploids 'Gentle Giant' and 'Trude
Webster'. In fact, over 30 of the 84 confirmed
polyploid elepidote rhododendrons have appeared
on lists of the best rhododendrons. Once these
polyploids appear on such lists, they are likely to stay.
The following hybridizers have worked
with or produced polyploid elepidote
hybrids:
Arends, Barlup, Blaauw, Bohlken, Bones, Boulter,
`Pink Pearl' a triploid, won the first Award of Merit Bovees, Brack, Briggs, Brockenbrough, Broughton,
in 1897 and continues as a garden-worthy plant as Bruns, Colombel, Croux et Fils, de la Sabliere, Drake,
34 • The Azalean / Spring/Summer 2015
Diirre, Elliott, Endtz, Evans, Farewell, Felix &
Dijkhuis, Fennichia, Fujioka, Gehnrich, Gill, Gra11,
Greer, Guyens, Hachmann, Hall, Hartman, Heinje,
Henny & Wennekamp, Hobbie, Horlick, Horsley,
Hiibbers, Johnson, Kavka, Kehr, Korn, Koster,
Larson, Laxdall, Lem, Loder, Lofthouse, Mangles,
Markeeta, McCullough, Moynier, Mossman,
Murcott, Naylor, O'Rourke, Ostler, Patterson,
Pearce, Perkins, Peste, Poulsen, Rabideau, Ragans,
Reuthe, Sagemuller, Sanders, Schannen, Schnupper,
Seabrook, Shapiro, Smith, Standish & Noble, Stead,
Stevenson, Stockman, Sumner, Thacker, Thornton,
van Nes, Van Veen, Vinson, von Martin, Waldman,
Walton, Waterer, Wieting, White, Whitney, Wilson,
Winberg & Smith, and Woodward.
It is noted that nearly as many hybridizers have
worked with confirmed elepidote polyploids as there
are confirmed polyploid hybrids. More importantly,
some of the hybridizers on this list are best known
for the polyploid elepidotes they have created. In
fact, polyploid elepidotes have been named in honor
of wives, mothers, grandparents, and queens.
Incidentally, Mossman, working with the diploid
deciduous azalea species R. occidentale, discovered
what Barlup later discovered working with hybrid
elepidotes: diploids are much more likely to accept
pollen from tetraploids than tetraploids are to accept
pollen from diploids. We found this to be true for
our crosses and have addressed this topic in more
detail elsewhere(Perkins et al. 12/2009). Breeding
with polyploid elepidotes is not an easy task, and
is fraught with low fertility in seed set and low
viability in seed germination. This explains why so
few polyploids have been created to date, despite so
many hybridizers having attempted to use them as
parents.
Jim Barlup wrote the following about using
polyploid elepidotes as parents:
"I continue to test the pollen and plants which I
doubt for 3 or 4 years to determine their fertility
or sterility. If you cross a diploid with tetraploid
pollen you can achieve beautiful seedpods but their
germination is very difficult. 3% seed germination
for Point Defiance'. Obtained are both diploid or
tetraploid offipring. '(Barlup 1999)
Ron Naylor wrote the following about his best plant,
`Francis Augustus Storey', from a cross involving the
tetraploid 'Point Defiance':
Francis Augustus Storey' - Best of grex of four
plants from weak germination. One died in 2000
and another in 2001.' (Naylor 2010)
Dick Murcott wrote the following about the plant
he called `TT116'*:
7T116 — [(`ean Marie de Montegue' X
degronianum var. yakushimanum) X 'Grand
Slam7. Only one seed from this cross germinated.
Looks like a tetraploid. Pink. Looks like 'Trude
Webster' but is definitely a seedling.' (Murcott
2010)
Barlup, Murcott, and Naylor each encountered
both the wonder and puzzlement presented by
polyploid rhododendrons. We have discovered for
deciduous azaleas that seed produced from tetraploid
X tetraploid normally has high rates of germination,
but germination from diploid X tetraploid crosses
varies greatly but is often poor. To read about Frank
Abbott's encounter with the wonders of working with
deciduous azaleas of different ploidy levels see 'Frank
Abbott's Village of Azaleas' (Perkins et al. 09/2009)
or 'Margaret Abbott' is a Tetraploid' (Perkins et al.
2011).
The following people and organizations
donated samples for this research
without whose generous donation of time
and material this work could not have
progressed:
John Abbott, Jane Adams of White Cloud Nursery,
Charles Andrews, Vivian Abney of East Fork Nursery,
Living Collection of Arnold Arboretum, Natural
Collection of Audra State Park, Living Collection of
Bartlett Arboretum, Jim Barlup, Norman Beaudry
of American Rhododendron Society Seed Exchange,
Jane Brooks, Joe Bruso, Werner Brack, Ned
Brockenbrough, Natural Collection of Canobie Lake
NH, Dick Cavender, Clarice Clark of Western North
American Rhododendron Species Project, Living
Collection of Connecticut College Arboretum,
Marc Colombel, Alfred Cook, Mike Creel, Bruce
The Azalean / Summer/Spring 2015 • 35
Untested Named Elepidote Hybrids We Suspect of Being Polyploid:
Adelheid' *
Aggie'
Aibette'
Alibaby'
Andantino'
Aperitif'
Arden Primrose'
Ariel Sherman'
Arnold Piper' ##
`Arthur Ostler'
`Baba'
'Be! Air'
`Bellevue'
`Bernard Crisp'
`Bernard Shaw'
`Bohlken's Kronjuwel'
`Boskoop Concorde'
`Canadian Beauty' ##
`Cara Meg'
`Castanets'
`Comte du Parc'
`Courtenay Duke'
`Diane Marie'
`Diane Titcomb'
`Diderk'
`Direktor Siebert'
`Doris Nolan'
`Dorothy Peste Anderson'
`Double Drake'
`Edward Cornelius'
`Elizabeth Titcomb'
`Ester Grace'
`Eureka Maid'
`Fiona Wilson'
`Flensburg'
`Forever Violet'
`Fragrant Sensation' ##
`Francis Augustus Storey' ##
`Garnet'
`Gill's Gloriosa'
`Ginette'
`Goliath'
`Grab Ya ##
`Gwen Bell'
`Hachmann's Anastasia'
`Hachmann's Kristina'
36 • The Azalean / Spring/Summer 2015
`Hachmann's Pinguin
`Hachmann's Veronika
`Heat Wave'
`Heinje's Schneewittchen'
`Heinje's Venezia
`Helen Druecker'
`Horizon Serenity' ##
`Humoreska'
'Ham Apricot'
'Earn Orange'
`Inheritance'
`Isobel Milk'
`Janet Ward'
`Jean Lennon
`Jean Marie Variegated'
`Jeanne Yvonne'
`Jenice Coffey'
`Julie Titcomb'
lusta Pink'
`Kareness'
`Kathy Ann Pieries'
`Kay Too'
`Kranenburg'
`Kranenkorn'
`Kranenrosette'
`KSW'
`Leonardslee Giles'
`Lilian'
`Lou-John Gem'
`Madah Jean'
`Maimorgen
`Malaga'
`Margaret Mack'
`Marie Oliva Schlickova"
`Marion'
`Mary-Ed'
`Maureen Ostler'
`Melville'
`Miss Kitty'
`Mistake'
Nicandra Newman
'Onkel Dines'
`Orrie Dillie'
`Patricia Jacobs' ##
`Peggy Bannier'
`Pink Perfection
`Pink Petticoats'
`Pink Titan'
`President Kennedy'
`Pride of Roseburg' ##
`Princess Debiann
`Prinzessin Inka'
`Professor Horst Robenek' ##
`Qualicum's Pride'
`Record'
`Red Walloper' ##
`Rheinzauber'
`Robert Korn'
`Rosandra
`Rosa Millennium'
`Rose Marie'
`Rotha'
`Rubinpracht'
`Seraphine'
`Serengeti'
`Shalom'
`Shari Laurel'
`Sheer Enjoyment' ##
`Siegfried Sommer'
`Sierra Sunrise'
`Sigrid'
`Standishii'
`Tausendschiin
`The Duchess'##
`fitness Belle'
`TT 116' *
`Twins Candy'
`Vincent Van Gogh'
`Virgo' #
Vonnie Stockman
Walkiire'
`Walloper' ##
`Whidbey Island'
`White Swan'
`Wilhelm Schacht'
`William Avery' ##
## - Almost certainly polyploid
based on parentage and/or fertility
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Figure 2: Offspring from Triploids:
'Pink Pearl'
Clyburn, Hans Eiberg, Al Fitzburg, Robert Fox,
Harold Greer of Greer Gardens, George Hibben,
Living Collection of Highstead Arboretum, Steve
Hootman of Rhododendron Species Botanical
Garden, Don Hyatt, J. Jackson of Appalachian
Native Plants, Lindy Johnson of Azalea Society of
America Seed Exchange, Richard Jaynes of Broken
Arrow Nursery, Doug Jolley, Fred Knippel, Johnny
Larsen, Living Collection of Longwood Gardens,
Robert Maclntyre, Ron Miller, Dick Murcott,
Michael Medeiros of Planeview Nursery, Wayne
Mezitt of Weston Nurseries, George Newman, Peter
Norris, John and Sally Perkins, Ron Rabideau
of RareFind Nursery, Ellie Sather of Whitney
Gardens, Hartwig Schepker of Rhododendron-Park
Bremen, Natural Collection of Stoddard Bog NH,
Kristian Theqvist, Patrick Thompson of Donald E
Davis Arboretum, John Thornton, Hendrik Van
Oostand of Azaleatuin, Kathy Van Veen of Van
Veen Nursery.
Despite having created this new suspected
polyploid list, our four-year journey of testing
suspected polyploids has shown that only about
half will turn out to be polyploids. Some such as
`Fragrant Sensation', 'Grab Ya', 'Pride of Roseburg',
and 'Sheer Enjoyment', having both parents as tested
tetraploids, are almost certainly polyploids. In the
list above,. we have marked, using the double pound
sign (##), a dozen or so we think are the most likely
polyploids based on parentage and fertility The
only way you can know for certain whether a plant
is an actual polyploid is to obtain a fresh sample
from a reliable source and test it under laboratory
conditions.
Most in this suspected list are known to have at least
one polyploid parent, be a sibling of a polyploid, or
be a parent of one or more polyploids. However, both
triploid and tetraploid hybrid elepidotes have been
shown to be capable of producing diploid offspring
when the other parent is a diploid. Many hybrids
on our suspected polyploid list do have one parent
suspected of being a diploid. In other words, a diploid
can have a polyploid parent or sibling. Moreover, two
diploid parents can produce a polyploid offspring, so
having a polyploid offspring does not ensure either
parent is a polyploid. Having a polyploid parent or
The Azalean / Summer/Spring 2015 • 37
one of two mechanisms.
Two diploids can cross
where one diploid parent,
instead of providing one
set of chromosomes,
67.410.
provides two, resulting in
as Irina
an
offspring that has three
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1.••■•■•■•■ ••■
mechanism for creating
triploids.
Figure 3:The pedigree of 'The Duchess', a suspected polyploid,
Ploidy results suggest
showing the 23 non-distinct polyploids in its ancestry.
that triploids such as
sibling greatly increases the chances that a plant is a Anita Gehnrich', 'Grace Seabrook', `Markeeta's
polyploid but is no guarantee. Whereas, being highly Flame', `Markeeta's Prize', `Solaridity', and 'Taurus'
fertile reduces the chances that a plant is a polyploidy, were most likely created by this unreduced mechanism.
On the other hand, a diploid parent and a
especially if one of that plant's parents is a known
diploid. A popular hybrid with polyploid ancestry tetraploid parent can cross where the diploid parent
and few named offspring is an excellent candidate for provides one set of chromosomes and the tetraploid
parent provides two sets of chromosomes, resulting
our list of suspected polyploids.
Based on looking at parentage and the number in an offspring with three sets of chromosomes. This
of offspring of named hybrids plus confirming 24 is referred to as the normal meiosis interploidy
polyploid hybrids with research done on 48 additional mechanism for creating triploids. Ploidy results
suspected polyploids in 2012, we conjecture that our suggest that triploids such as 'Anna Rose Whitney',
lists of known (84) and suspected (132) polyploids `Cotton Candy', 'El Camino', 'Hank's Folly',
contain the vast majority of what is almost certainly `Julia Caroline, 'Lady of Spain, 'Lucky Strike,
less than 200 polyploid elepidote hybrids registered `Lydia', 'Opal Thornton, 'Platinum Pearl', `Rwain',
`Steredenn', 'Sugar Pink', 'Super Dog', and 'Van were
prior to 2000.
In short, there are no rules of thumb for "knowing" most likely created by this normal meiosis interploidy
the ploidy of the offspring for hybrid elepidotes mechanism.
Offspring are documented for the following
if the parents are of mixed ploidy levels or either
parent is a triploid or pentaploid. Diploid X diploid triploids: Anna Rose Whitney', 'Betty Wormald',
will almost always (but not always) create diploid `Broughtonii', 'Cotton Candy', 'Cynthia', `Gomer
offspring. Tetraploid X tetraploid will almost always Waterer', 'Lydia', 'Pearce's American Beauty', 'Phyllis
(but not always) create tetraploid offspring. However, Korn', 'Pink Pearl', 'Platinum Pearl', `Rwain',
diploid X tetraploid and tetraploid X diploid, which `Solidarity', 'Taurus', and 'Val d'Aulnay' (Fig. 1).
are normally associated with producing triploid The common belief that triploids are always sterile as
offspring, have been shown to produce a combination both seed parents and pollen parents is challenged by
of diploids, triploids, and tetraploids when working these findings. Triploids such as 'Pink Pearl', 'Phyllis
Korn', `Rwain' and 'Taurus' appear to be partially
with hybrid elepidotes.
fertile as both seed and pollen parents (Fig. 2). In
Triploids, Fertile Triploids and Triploids as the fact, triploids can be the progeny of triploids. Based
on parental documentation, 'Broughtong, 'Pink
Progeny of Triploids
Triploids are normally believed to be produced by Pearl, `Gomer Waterer' and 'Phyllis Korn represent
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four consecutive generations of triploids (Fig. 1).
Three sports of the triploid 'Pink Pearl' were
ploidy tested: 'Ebony Pearl' and Topsvoort Pearl'
tested as triploid whereas intriguingly, 'Mother of
Pearl' tested as diploid (Fig. 2).
Diploids can be the progeny of triploids. Diploids
such as 'Graf Zeppelin', 'Hurricane', 1.G. Millais',
and 'Summer Peach' are documented to have a
triploid parent. In the case of 'Graf Zeppelin, the
triploid 'Pink Pearl' is documented as the seed
parent (Fig. 2). Although a diploid, 'Graf Zeppelin'
exhibits characteristics often associated with named
polyploids.
Tetraploids can be the progeny of triploids:
`Countess of Derby', a tetraploid, is documented
to have two triploid parents, namely 'Pink Pearl'
and 'Cynthia (Fig.1). Tetraploids such as Antoon
van Welie', 'Gentle Giant', and 'Grand Slam' are
documented to have a triploid parent. In the case
of Antoon van Welie', the triploid 'Pink Pearl' is
documented as the seed parent (Figs. 2 and 3).
Marc Colombel donated some of his suspected
polyploid hybrid seedlings for testing. Noteworthy
is that four seedlings of `Rwain' X TEngin' tested
as tetraploid. `Rwain, the seed parent, is a triploid.
TEngin', the pollen parent, is a tetraploid. Moreover,
three seedlings of the cross of the tetraploid
`Horizon Monarch' with the triploid `Rwain' tested
as tetraploids but one seedling tested as triploid.
Figure 2 suggests that a triploid parent, for
example 'Pink Pearl', can produce offspring that are
diploids, triploids, and tetraploids. Figure 1 suggests
that pentaploids such as 'White Ginger' are also
possible from a triploid parent.
In the 1930s, C. D. Darlington showed that
triploids could be fertile. Moreover, Darlington
confirmed a third mechanism for creating triploids.
Darlington showed that the chromosome set in
triploids may split unevenly during meiosis to
form a bell-shaped curve distribution. This means
that most gamete cells form near the midpoint of
1.5x, with a few having lx and 2x chromosomes.
So in a few cases, a triploid parent can act as a
diploid contributing one set of chromosomes or as
a tetraploid contributing two sets of chromosomes.
Our ploidy results, (Perkins et al. 10/2010) when
combined with the documentation of parentage,
strongly suggest this third distributive meiosis
mechanism does occur for fertile triploid elepidote
rhododendrons. Hans Eiberg has determined in
controlled lab experiments that for rhododendrons,
hybrid triploid pollen is sometimes just as viable as
any hybrid diploid pollen.
Tetraploids and Diploids as the Progeny
of Tetraploids
Tetraploids such as 'Doreen Gale', 'Gorgeous
George', and 'Legend' have been created by the
normal meiosis mechanism where both parents are
tetraploids. Tetraploids such as 'Horizon Monarch',
lem's Monarch', TEngin', 'Point Defiance', and
`Very Berry' may have been created by the unreduced
mechanism of a diploid parent with the other parent
being a tetraploid.
Justin Ramsey's work with newly created
neotetraploids suggests that such neotetraploids may
experience irregular meiosis. Ramsey suggests that
in some instances a neotetraploid may contribute
only one set of chromosomes to the offspring. For
the purposes of this article, we refer to this as the
super-reduced mechanism.
Diploids such as 'Rendezvous', `Irmelies', 'Orange
Leopard', and 'Stony Brook' may have been created
by this super-reduced mechanism. In the case of
`Rendezvous', the tetraploid `Marinus Koster' is
documented as the seed parent.
Noteworthy is that one seedling of 'Horizon
Monarch' that had been open-pollinated tested as
diploid. The actual plant of 'Horizon Monarch' that
was the parent of this particular diploid seedling tested
as tetraploid. Other seedlings from the same seedpod
tested as tetraploid. 'Pink Goliath', a tetraploid (4x),
is the result of WAntoon van Welie' (4x) X 'Professor
J. H. Zaaijer' (2x)] X 'Annie E. Endtz' (3x)), where
each parent contains 'Pink Pearl' (3x) in its heritage.
The pentaploids, `Haithabu' and White Ginger',
have a tetraploid parent. Our ploidy results suggest
that tetraploids may produce diploid, triploid,
tetraploid, and pentaploid offspring.
The Azalean / Summer/Spring 2015 • 39
Normal, Unreduced, Super-reduced, and Distributive Meiosis: By the Numbers
A diploid rhododendron has 26 chromosomes. Normally a diploid rhododendron as a parent splits
in half during meiosis, contributing 13 chromosomes to the offspring. A tetraploid rhododendron has 52
chromosomes. Normally a tetraploid rhododendron as a parent splits in half, contributing 26 chromosomes
to the offspring. A triploid rhododendron has 39 chromosomes. Half of 39 is between 19 and 20. Darlington
showed that if a triploid having 39 chromosomes were to split, it would split mainly 19/20 but also, to ever
decreasing occurrences, 18/21, 17/22, 16/23, 15/24, 14/25, and 13/26, where the splitting as 13/26 occurs
the least frequently. This splitting would form a bell shaped curve between 13 and 26.
Thus, in principle, for rhododendrons:
diploid x diploid usually results in a diploid since 13 + 13 = 26.
tetraploid x tetraploid usually results in a tetraploid since 26 + 26 = 52.
diploid x tetraploid usually results in a triploid since 13 + 26 = 39.
diploid x unreduced diploid can in a few instances result in a triploid since 13 + 26 = 39.
unreduced diploid x tetraploid can in a few instances result in a tetraploid since 26 + 26 = 52.
diploid x super-reduced tetraploid can in a few instances result in a diploid since 13 + 13 = 26
diploid x triploid can in a few instances result in a diploid since 13 + 13 = 26 or in a triploid since
13 + 26 = 39.
triploid x tetraploid can in a few instances result in a triploid since 13 + 26 = 39 or in a tetraploid since
26 + 26 = 52.
Noteworthy, other researchers have found that the offspring of triploids are often aneuploids. For
rhododendrons, an aneuploid would have a chromosome count slightly more or less than 26 (2x), 39 (3x), 52
(4x), 65 (5x) or other multiples of13 (x = 13). The unstable meiosis associated with triploids and neotetraploids
most likely means that some of the rhododendrons listed above as diploid, triploid, or tetraploid do not have
exactly 26, 39, or 52 chromosomes but instead, have close to these counts. Flow cytometry being a method
of weighing sets of chromosomes rather than counting the number of chromosomes is not well suited to
separating euploids, which have a normal chromosome count, from aneuploids.
Summary
Named hybrid elepidote polyploid rhododendrons have played an important role in the garden for more
than 150 years. The physical characteristics associated with polyploid rhododendrons have proven to be
highly desirable by gardeners since their introduction by Broughton, Standish & Noble, and Waterer. The
ploidy of more than 170 named elepidote rhododendrons is listed above. Although all species of elepidote
rhododendrons have tested as diploid to date, more than 80 named hybrid elepidote rhododendrons have
tested as polyploid. Eighty-nine samples tested as diploid, 51 as triploid, 31 tested as tetraploid, and two as
pentaploid. Twenty-two tested diploids are documented to have a polyploid parent. Four tested diploids are
documented to have a tetraploid parent.
Triploids can be fertile as both seed and pollen parents, and triploids are able to produce diploid, triploid,
tetraploid, and pentaploid offspring. Tetraploids also are able to produce diploid, triploid, tetraploid, and
pentaploid offspring. The mechanisms of normal, distributive, unreduced and super-reduced meiosis are
discussed. All ploidy results presented here are based on flow cytometry.
This research was guided by the work contained in the following:
Hybridization of Rhododendron Elepidote Polyploids by Jim Barlup pg 1-4 1999
http://www. rhododendron. fr/articles/article35c. pdf
Rules of Engagement.• Have Pollen - Will Travel by John and Sally Perkins 2009
http://rosebayblog.blogspot.com/2009/12/rules-of-engagement.html
40 • The Azalean / Spring/Summer 2015
Ploidy Levels and Relative Genome Sizes of Diverse Species, Hybrids, and Cultivars of Rhododendron by Jeff
Jones, Thomas G. Ranney, Nathan P. Lynch, and Stephen L. Krebs pg 1-8 2007
http://www.holdenarb.org/education/documents/Joneseta12007.pdf
Ploidy Breeding and Interspecific Hybridization in Spathiphyllum and Woody Ornanamentals by Tom
Eeckhaut pg 1-184 2003
http://lib.ugent.be/fulltxt/RUG01/000/788/476/RUG01-000788476_2010_0001 AC. pdf
Meiosis in Polyploids Part I. Triploid and Pentaploid Tulips by W. C. F. Newton and C. D. Darlington pg
1-15 1929
http://www.springerlink.com/content/d017424p78822113/
Neopolyploidy in Flowering Plants by Justin Ramsey and Douglas W. Schemske pg 1-52 2002
http://www.botany.wisc.edu/courses/botany_940/07Polyploidy/papers/RamseySchemske02.pdf
Posts for each sample ploidy tested are available on the Rosebay Blog. Posts have been grouped using tags
to promote easy viewing of related posts. Please weigh in by exploring these posts to discover the wonderful
world of ploidy in the Rhododendron Garden. 2012
http://rosebayblog.blogspot.com/search/label/U of Coimbra/
Portions of this research were funded by an Arnold Arboretum of Harvard University Deland Award,
an American Rhododendron Society Massachusetts Chapter Research Grant, an American Rhododendron
Society Research Grant, and an Azalea Society of America Research Grant.
Sally and John Perkins are members of the ASA Vaseyi Chapter and the ARS Massachusetts Chapter.
References
Barlup, J. 1999. L'hybridation de rhododendrons elepidote polyploides
http://www.rhododendron.fr/articles/article35c.pdf 1-4.
Greer H, 1972. 'Trude Webster' http://scholar.lib.vt.edu/ejournals/JARS/v26n2/v26n2-greer.htm
Mossman, F. 1972 With Camera, White Umbrella, and Tin Pants. In R. occidentale Heartland.
http://scholar.lib.vt.edu/ejournals/JARS/v26n4/v26n4-mossman.htm
Murcott, R. 2010. Selected Rhodo Seedlings. http://www.murcottgarden.com/select-seedlings
Naylor, R. 2010. Rhododendrons http://219.88.101.105/e16.html
Perkins J. and Perkins S. 2009. Frank Abbott's Village of Azaleas.
http://rosebayblog.blogspot.com/2009/09/abbott-azaleas.html
Perkins J. and Perkins S. 2009. Rules of Engagement: Have Pollen - Will Travel.
http://rosebayblog.blogspot.com/2009/12/rules-of-engagement.html
Perkins J. and Perkins S. 2010. Audra State Park: A Ploidy Haven
http://rosebayblog.blogspot.com/2010/09/audra-state-park-ploidy-haven.html
Perkins J. and Perkins S. 2010. 'Pink Pearl' is a Fertile Triploid.
http://rosebayblog.blogspot.com/2010/10/pink-pearl-is-fertile-triploid.html
The Azalean / Summer/Spring 2015 • 41
Perkins J. and Perkins S. 2011. 'Margaret Abbott' is a Tetraploid.
http://rosebayblog.blogspot.com/2011/06/margaret-abbott-is-tetraploid.html
Ranney, T and Jones J. 2008 Understanding Polyploidy: Insights Into the Evolution and Breeding of
Azaleas.
http://www.ces.ncsu.edu/fletcher/staff/tranney/understanding_polyploidy2008.pdf 1-4
Zhou, W, Gibbons, T, Goetsch, L, Hall, B. Ranney, T, and Miller, R. 2008 Rhododendron colemanii: A
NewSpecies of Deciduous Azalea (Rhododendron section Pentanthera; Ericaceae) from the Coastal
Plain of Alabama and Georgia.
http://www.ces.ncsu.edu/fletcher/mcilab/publications/zhou-etal-2008.pdf 1-7
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•Er
Mark your Calendars!
April 20 - April 24, 2016
Legicies
F
Williamsburg, Virginia
A Joint Convention of the American Rhododendron Society
and the Azalea Society of America
These dates are at the opening of Historic Garden Week in Virginia, one of the most
beautiful times of the year in the region. This convention will be staged at the Fort
Magruder Hotel and Conference Center, conveniently located within a mile of Historic
Colonial Williamsburg.
Go to the Convention 2016 website for full details of this exciting event!
arsasaconvention2016.org
Contact persons are Rick Bauer, 757-833-7737, or Don Hyatt, 703-241-5421.
42 • The Azalean / Spring/Summer 2015