Two nice variegated Hoyas from Thailand

Hi Chanin,

 

The Hoya pachyclada is particularly fine. Do you find that these variegated hoyas burn more easily in strong light, than the all-green leaved versions?

 

Matt

Dear Matt, Actually, I talked with the owner, he said the plant prefers more intense sun! (he means a have day direct sun) than under 70% lath hoese. I think because the more white colored could reflex the sun-ray and also Hoya pachyclada , with its wax cuticle on the succulent leaf, is one of the most heat & drought tolerant species.

 

And last night, I found the picture of Micholitzia obcordata and some more interesting topic to show.  I will scan and post to the forum at the office today.

 

Chanin

Chanin, I'd have to see actual flowers to be sure but I believe that what you have is not Hoya pachyclada.  I believe it is Hoya subquintuplinervis.

 

The hoya generally sold as Hoya subquintuplinervis is not that species.

 

Hoya subquintuplinervis is frequently sold as Hoya pachyclada.

The two look a lot alike even when in flower but a microscopic examination of the flower shows great differences.  The only conspicuous difference in in the leaf shape.  Hoya subquintuplinervis leaves are almost round, while those of Hoya pachyclada are obovately oblong (that's oblong but somewhat narrower at the base.  Both are light grayish green with a suede-like surface (top and bottom).

 

I you get follicles, the follicles of the two are very visibly different too.

 

One is  about 2 to 3 inches long and only about 1/4 to 3/8 inch in diameter while the other is about 1.5 inch long and about a 1/2 inch in diameter (looks like one of those little gherkin pickles.

 

So, going entirely on the leaf shape, I'm guessing that what you have is Hoya subquintuplinervis.

 

Chris

Dear Mom Chris,

I've posted one more picture which show a better detail of leaves for any determinations to this variegated Hoya from Thailand.

 

Chanin

Chanin, there is no way I can tell what your species is, without being about to examine flowers microscopically.

 

I have made a chart, showing differences between Hoyas pachyclada & subquintuplinervis.  It can be found in I The Hoyan, vol. 19, #3, Jan. 1998 on page 69.

 

I tried to post it in one of my albums but can't.  Discovered that they count all of the pictures, attachments and documents anywhere on the forum as one unit so I really am out of space now.  On the old forum I had two albums under two names so was able to double the storage space, but I'm getting old and senile.  I can't remember how I did it.

 

I'll e-mail you and anyone else who'd like a copy of that page.

 

The leaf differences I've already noted, as well as the differences in the follicles.

 

Other differences are:

 

Calyx of H. subquintuplinervis:  Sepals overlap at bases; shape is triangular and pointed at tips but not sharply.

Calyx of H. pachyclada: Sepals are not overlapped at bases; shape is round without points at tips.

 

Calyx of Hoya subquintuplinervis has ligules at each sinus but also what appears to be shorter ligules completely surrounding the carpels at their bases.

Calyx of Hoya pachyclada has ligules at each sinus -- no others present.

 

Pollinaria of H. subquintuplinervis:  Pollinia narrow in ratio to length; retinaculum pointed at top with top half almost trinagular in outline.

Pollinaria of H. pachyclada: Pollinia much broader in ratio to length, especially at the top; retinaculum rounded at top with what appears almost like short arms at the sides near the top.

 

I had the two species sitting side by side on my back deck during the summer of 1997.  Both bloomed profusely.  Hoya subquintupliners was never pollinated -- no follicles.  Hoya pachyclada produced 8 follicles.  I'd have to go to my notes to tell you which were single and which were double.  I do recall that some were double pods (2 on one pedicel).  I point that out because I read someone else's writing that all hoya follicles aborted one of the follicles.  Tain't so.

 

I am grateful to Dr. Obchant Thaithong for help with these two species.  It was she who sent me copies of holotype material and who furnished me with details on the follicles of Hoya subquintuplinervis.

 

If any want a copy of page 69 of The Hoyan 19:3, send me an e-mail and I'll send it back.  Meantime I'm going to try hard to figure out how to put up another album using another name so that I can restore some of the pictures I've had to delete and add some others, such as this one.

 

Chris

I have posted a picture of the two species in question. Both are the same age and in 100mm pots. They are grown in greenhouse conditions and the size difference between the species is very apparent.

The feature I have observed are H. subquimtuplinervis tends to twine while H. pachyclada tends to be a shrub. There are also differences in leaf shape that appears to be constant with H. subquintuplinervis remaining more or less rotund with a mucronulate end, and H. pachyclada the leaf shape is elliptic narrowing at the base with an acute tip.

David, I will need to examine flowers of the hoya on the left in your picture to be sure what I think it is, however, I believe you are wrong about it.  It has two umbels almost ready to open now so, in a few days I'll be able to examine them microscopically and in two or three weeks will have pictures of those flowers to send off to you.  At this point, my very biased opinion is that it is NOT Hoya pachyclada.

 

Its leaves do not look right and my observation is that neither of the two most available clones  species show any inclination to twine.  The hoya that I consider to be Hoya pachyclada has more slender stalks.  They tend to sprawl and cascade downward when not tied to supports.  The internodes are longer as are the leaves.

 

The Hoya I consider to be Hoya subquintuplinervis has stalks as thick as my fingers and closely spaced, almost round leaves.

 

Your plant, which is one I have looks, under my conditions like Hoya lambii, without the funnel, until it blooms.  The flowers look like Hoya subquintupinervis flowers but I have not photographed them microscopically to confirm this.  I just assumed it to be a different clone of a variable species.

 

The one I consider to be Hoya pachyclada matches both type material and the published description as far as leaf features go but, of course, I can't see the floral details of the flowers looking at only pictures of herbarium specimens. I have some sketches of these made by Dr. Thaithong.

 

The same can be said of the one I consider to be Hoya subquintuplinervis. Dr. Thaithong's correspondence indicated that she thought both the same species, at least that was my impression, however the eight follicles that formed on my Hoya pachyclada plant was ample proof that two species were involved.

 

The one I consider to be Hoya subquintuplinervis was sold to me by Ted Green during one of those brief periods when he was willing to sell to me.  He labeled it as "Hoya pachyclada untypical form."  PLEASE NOTE --- I did NOT say and Ted Green did NOT say, "untropical form" as many of our readers, read that statement and immediately write wanting to know where they can buy the Hoya pachyclada that can be grown outdoors in temperate zones -- Sorry folks, it doesn't exist.

 

I cannot argue that your plant is or is not correctly labeled until I have examined them microscopically (which I should have done last time it bloomed but didn't) but I am 100% certain that one twining and one not twining is not a reliable feature in distinguishing between these two species.  I am sure it is possible that there is a twining clone of one or both of these species.  I'm only familiar with the two that I believe are correctly identified and the one that I will examine when it blooms (in a few days).

I have added pictures of the parent stock of the plants in the comparison picture. The one labelled H. subquintuplinervis is the Ted Green plant and clearly shows the thick stems and twining habit. The plant labelled H. pachyclada is a collected plant and a site picture shows the shrubby habit and thinner less succulent leaves. CB has described the characteristics of these plants. A walk in a Thailand plant market soon educates the eye to the differences between the two  species, the wild collected plants are quite different. I think there may be a third species but it may be a hybrid so we should not go there.

David, I agree that your new picture, labeled Hoya subquintuplinervis, is that species but I see nothing in your picture that would lead me to believe that it twines.  It appears to grow almost straight up that support.  I've grown this one for years and it has never twined.

 

Also, as a point of clarification, this is not Ted Green's "Hoya subquintuplinervis."  Ted sells a species, formerly called "H. sp. Chieng Mai" as Hoya subquintuplinervis.  I believe that species to be one of long list of Hoya pottisii clones.  It looks identical to a picture I have that is reputed to be the "type" of Hoya pottsii.  I thought this should be pointed out because experience has taught me that many people will assume we're talking about that species when we say Ted Green's Hoya subquintuplinervis.

 

The one you have labeled as Hoya pachyclada doesn't look at all like the one I've grown as Hoya pachyclada.  As I noted, I have yours and it was in bud a few days ago but when I checked this morning all the buds had blasted so I'll have to wait until it blooms again to examine the flowers, unless Lesli's blooms soon.   

 

When I get blooms again, I dredge this thread out and report my findings.

 

Chris