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Rhododendron Hobbiense"

Rhododendron Hobbiense a new species? - March 20th March 2006

R. Hobbiense, blomsterklase hos CA Lehmann, HE R. Hobbiense, plante hos J.C. Birck, JCB Knop hos J.C. Birck, JCB
Overside af blad hos HE, H. Eiberg Underside af blad hos HE, H. Eiberg Kapsel hos HE, H. Eiberg
Kapsel - ung hos HE, H. Eiberg
Planten om vinteren hos HE, H. Eiberg
R. Hobbiense blomsterklase hos Carl Adam Lehman hos Carl A. Lehmann, H. Eiberg

R. Hobbiense - described by Hans Eiberg ; 20th March 2006
Synonymes: R. 'Hobbies bureavii'; poluninii aff.; R.luciferum sold by K. Cox

Lanata subsection:

About R. Hobbiense:

Not a hybrid: gave uniform offsprings with R. yakushimanum. The R. Hobbiense can produce lots of seeds by self-pollination.
Seeds from Hsu expedition in 1937 to Tibet were sendt to Hobbie (Carl Adam Lehmann)
Leaves ->7-16-> cm long 3-4 cm broad, flat, dark green, glossy
Leaves with thick yellowgreen (new leaves) -> yellow brown flat indumentum (1 year old leaves),
not red-brown and cottony on the lower leaf surface. Unilayer* ramiform indumentum
New growth with brown tomentum on upper leaves
Petiole with white indumentum, also red-brown hair in May
Corolla cream-yellow, 3.5-4cm long. Lobes 5, -13 mm (like R. luciferum)
Pedicle 8-15mm Ovary wollen, no glands
Calyx minute, 0.5-1mm long. Outsite and margin densely yellow tomentose

After 10 years 1 m high without fertilization.
No winter damage at > -20C R. lanatum var. lanatum, R. tsariense and R. lanatum var. luciferum are more tender.

This species is not:
R. luciferum (or R. lanatum var. luciferum) orange/red-brown cottony indumentum, and leaves 8-14cm
R. tsariense (small leaves 2-4cm, corolla white-pink)
R. flinckii (red brown indumentum)
R. circinnatum (ovary with glands -> hybrid!)
R. lanatum (brown-coffeebrown indumentum)
R. poluninii (leaves 5-7 cm, corolla white-pink)
R. lanatoides (more narrow leaves and indumentum different: thicker, glossy, recurved; white corolla)
(leaf basis and apex tapering)

R. luciferum after Davidian's book
R. lanatoides at Muncaster: photo: Kurt Hansen
R. lanatum at Muncaster: photo: Kurt Hansen
Subsec. Lanata leaves (except "hobbiense") var.luciferum #6 April 24, 2006
R. lanatum var. luciferum and R. Hobbiense leaves May 10, 2006
Lanata leaves. 1 hobbiense, 2 luciferum, 3 Cox-luciferum, 4 lanatoides, 5 lanatum, 6 flinckii, 7 lanatum dwarf, 8 tsariense New July 26, 2007
3) Cox form of luciferum has only a very thin yellow indumentum 2) R. lanatum var. luciferum has a very thick red brown indumentum usefull in an oil lamp.
Cuts of leaves (thickness) of R. lanatum Cox (var. luciferum) brown thick indumentum, R. lanatum Sikkim, R. hobbiense and R. flinkii
None of these are R. circinnatum which has glands. April 2008

April 2009

Hobbiense hair: Foto Klaus Yde R. lanatum var. luciferum (Bartholomew) hair: Foto Klaus Yde Indumentum (hairs) from R. hobbiense and R. lanatum var. luciferum (Bartholomew). Foto Klaus Yde

Original plant(s) of R. Hobbiense: Few plants known from Hobbies Garden, Westerstede, Germany

* New Dec. 2007. Mike Robinson, John McQuire, Pam Hatward, Hans Eiberg, Carl Adam Lehmann found a very thin inner layer of special hair on this species on two different clones one from Hans Eiberg and one from Carl Adam Lehmann respectively
R. hobbiense could be an eglandular variation of R. circinnatum? and perhaps a Taliensa.
Carl Adam Lehmann: Prof. Hu send some seeds to Hobbie in 1937 from his expedition to Yunnan-Muli-Sichuan.
New, Dec 2006:
Plants raised from seeds possibly collected by Ludlow and Sherriff expedition in 1938 to Tibet (The Rhododendron and Camellia
yearbook 1959, page 42-48). Probably seed number 3589 or 3619. Also lanatum was found in the area # 3620, 6549, 6652 and
tsariense var tsariense #6657.

Common (grafed) plant in many collectors garden in Denmark- named: Hobbies bureavii or R. poluninii aff.

K. Cox plants sold as R. luciferum fits with "R. hobbiense" (after K.Cox's), but not with R.luciferum described by Davidian II, Chamberlain 1981 or
in the Rhododendronhandbook 1998.
A comparison in may 2007 (above) by H.E. shows that they are very different. K. Cox plant could be R. circinnatum ?

Generally, the phenotypical variation in a species is not narrow - and species are separated from each other by
larger phenotypical differences, such as structural differences in indument types (hair, color and forms).
An importent factor is also the distribution in the wild.
We have to wait until on a population studies in the wild, before we define the degree of this species phenotypical variation.

About R. lanatum var luciferum:

Thick redbrown indumentum on the lower leaf surface (somewhat like R. bureavii) Sold as R. lanatum with an
oblong oval leaf form (by Cox). Leaves 8-14 cm long, 2.5-3.5 cm broad.
R. lanatum var luciferum and R. hobbiense leaves New 10 May 2006

RSBG Flora of China, circinnatum Flora of China, lanatum var. luciferum
Some comments from Stephen Fox  30/9 2007

R. circinatum was found on the Bimbi La by Kingdon Ward in July, 1935.  (KW 11964).  This plant was originally 
classified by Davidian as a member of the Taliense Series (with a supposed resemblance to R. adenogynum).  
Chamberlain subsequently moved it (along with R. lanatoides) to the Lanata Sub-Section.  Flower colour white or pale yellow.

R.luciferum was found by Ludlow and Sherriff in May 1936 in and around the Lung Chayul Chu (LS1557), and by Ludlow, 
Sherriff and Taylor in 1938 (LST 3620, 6549, 6652), at and around Molo.  The flower colour was "lemon".

Both Ken Cox and I collected seed from Lanata plants on the Bimbi La (one species only).  Those plants have ramiform 
indumentum of in a yellowish colour and a coiled structure.  They conform to the description of R. circinatum, as do 
plants raised from their seed.  (However, Ken sold these plants as "luciferum" until this year.  He now calls them 

If you have a plant from the LST 1938 collections (above), it surely must be R.luciferum, as the name was so defined 
from these plants.  Certainly the indumentum should be reddish-brown, not the yellow-brown associated with T. circinatum 
(and R. lanatoides).

However, it seems to me that your "hobbiense" is most likely circinatum, as the leaves are basically similar and the 
presence or absence of glands on the ovary may not be critical.  I remember Elizabeth Hobbie telling me that her father 
was a great seed-collector.  When I asked where he had been plant-hunting, she replied "mostly England"!   So can you 
rely on the real provenance of your plants?

Mr Birck's plants seem different from the others and might well be R. luciferum.

Your survey of the Lanata omits Davidian's "tsariense magnum" and "tsariense trimoense", (with its 3-metre high variant 
at Muncaster) not to mention a plant sold by Glendoick in the 70's as "lanatum aff".  It's a low spreading dwarf with 
very thick indumentum.

31/9 2007 Comments to S. Fox H.Eiberg My R. Hobbiense has yellow-brown indumentum and not reddish-brown indumentum and my plant is the same clone as Birck's plant G. Dixon 10/10-2007 comment regarding Stephen Fox's remark about 'Hobbie's seed-collections' . He never collected seed out of English gardens and assumed the resulting seedlings to be good species. His definition of a 'good species' was anything that grew from seed that he'd received under a collectors' number from the RBG Edinburgh and he took this very seriously. Even the obvious natural hybrids such as 'erythrocalyx' he treated as species, purely because of their natural provenance. This attitude was of course a little uncritical but he certainly never collected just any old seed and sold the seedlings as species.
May 10 2006 from Gerald Dixon For about 25 years I was a close friend of Hans Robenek (sadly he passed away last year) and during his time as Hobbie's nursery-manager, also got to know Dietrich Hobbie a little. The plant we're talking about was always known as 'bureavii aff.': the best plant was growing beside the main pathway, was (in the late 80s) only about 60cm high and according to Hans Robenek, had never been known to flower. There were further seedlings, more open growing, that had flowered and this seems to be the plant that Carl Adam Lehmann and others grow? In the mid-eighties Peter Cox and his family were visiting Jan Wieting, also a good friend of Hans Robenek, and Jan took his guests to see Hans Robenek's garden/nursery in Linswege. According to Hans, Peter Cox saw the 'bureavii' and immediately said that this was in fact Rh.poluninii. Since then, this name has seemed to travel to Scandinavia, possibly due to the annual visits of the 'Danes' to Linswege. If you look at Cox's species book, on page 96 picture number 3 shows foliage extremely similar to 'hobbiense' (apart from the less shiny upper leaf surface) and certainly not what we normally grow as lanatoides. The picture of poluninii on page 98 shows much more rounded foliage that hobbiense, nothing like the typical tapered form. From the text on the following pages it seems that the main difference between luciferum and lanatoides should be the flower colour, yellow in luciferum and white in lanatoides. The open-growing form of hobbiense has white flowers as far as I know so this rules luciferum out. I've attached a photo of a small, unfortunately rather sickly plant of the compact hobbiense: the mature leaves have a definite olive shade which certainly separates this plant from what was usually considered to be bureavii in Germany. I have a plant of bureavii which originated from Hobbie with the typical thick stems and a near orange indumentum so I can't imagine Dietrich Hobbie assuming that these were the same species but he had to call it something? I think it's a great shame that Dietrich Hobbie's name has not been used for this plant so I hope you and other experts persevere with the argument.
Dear Carl and Hans, Dec 2007 John McQuire and I looked at the leaves you kindly sent of 'luciferum' 1* and hobbiense yesterday using his powerful microscope, and his long experience! 'Luciferum', as expected, keys out to circinnatum - bistrate with scattered small rosulate hairs underneath the thick layer of ramiform hairs which have the distinctive curly ended branches. We believe that all the Glendoick plants sold as luciferum are circinnatum, and their latest catalgoue suggests that they think so too. Hobbiense is very interesting. The indumentum is, in fact, bistrate, with widely scattered small rosulate hairs under the ramiform layer, which is even thicker than luciferum on the leaves we examined. You need high magnification to see the rosulate hairs. Now, the ramiform hairs look exactly the same as those on circinnatum, and these distinctive curly hairs do not occur, to our knowledge, on any other species. However your description states that there are no glands on the ovary of Hobbiense, and dosn't mention glands on the pedicel or calyx, all of which are mentioned by Davidian. The question that arises, therefore, is what do the flowers of 'luciferum' (= circinnatum) look like? Are there glands present at all, and is Davidian's description wrong (unlikely, we think). Has it flowered in Denmark? We have never seen a flower. We should also very much like to see the flowers of Hobbiense as well, and hope you would send a truss of each if and when. Tentatively we have to say that Hobbiense is an eglandular expression of circinnatum, but we have to make sure. Thanks for opening up this fascinating puzzle. There should be a publication in this eventually! All the best for Christmas and the New Year, Mike Robinson 1* 'luciferum' was the R. lanatum, Bartholomew 185B-76.0891D Benmore
DETERMINATION by J.F.J. McQuire May 2009 of two small packets containing 4 corollas of R. hobbiense (sic) ( leaves sent in 2008 –none in 2009). From Hans Eiberg. Leaves: Oblong-elliptic 8-12 cms long 2.5 to 4.5 cms wide.: Apex –some abruptly acute and some abruptly acuninate : base rounded. Upper Surface: Shining dark green , floccose in grooved midrib- mainly towards the base- detersile on old leaves. Lower Surface: Covered with a thick dark brown (some rust-coloured) continuous UNISTRATE indumentum of thick short-stemmed dendroid hairs (superficially appearing ramiform) with long and very long filamentous branches. Petiole: Densely tomentose with hairs as lower lamina. Inflorescence: Corolla: Unknown number in truss (See heading) funnel-campanulate : narrow base 3.5 to 4 cms. long: 5-lobed minutely emarginate. Very pale yellow without spots. Stamens: Unknown number (diffused and part decayed in packets) Unequal, very pubescent third of way from base. ie . the height of the ovary. Style: 2.5 cms glabrous.: eglandular Pedicel: 1 –1.8 cms long: DENSELY FLOCCOSE with some hairs having red resinous parts which can be mistaken for glands : EGLANDULAR. Calyx:: Small, nearly a mere rim: green: floccose/ pubescent Ovary: DENSELY TOMENTOSE similar to the pedicel hairs : conoid : EGLANDULAR