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Post by Brian Barnes on Dec 17, 2008 16:59:17 GMT
Hello Friends, Here's an interesting update on the FCPS website that all admirers of Drosera indica may find rather interesting, regarding a 'white flowered' form with red glands existing only on the back of the leaves, that I am currently growing and experimenting with... You can find my documentation/report here; www.floridacarnivorousplantsociety.org/documentationresearch.htmHappy Growing, Brian. |
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Post by Dave Evans on Dec 17, 2008 21:22:24 GMT
Dear Brian,
I think this is probably an adaptation to protect the growing leaf buds from intense lighting... As you have noticed, the red is densest on the growing leaves and may serve no purpose once it is fully grown.
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Post by Brian Barnes on Dec 18, 2008 12:01:33 GMT
Interesting theorum, Dave... You could be on to something!  Thanks for your input... Happy Growing/Holidays, Brian. |
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Post by stevestewart on Dec 18, 2008 13:11:30 GMT
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Post by Dave Evans on Dec 19, 2008 3:41:22 GMT
What I really find intersting is these red glands do not appear to be useful for trapping prey... Maybe maybe they work in attracting prey by contrast so the larger, clear glands can trap them...
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fred
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Post by fred on Dec 21, 2008 4:26:03 GMT
You should take into consideration that this occurs in a form which has a second deviation: white flowers. My guess is there's something going on at the level of gene expression which becomes apparent in both flower color and glandular growth. Don't forget that mutations don't occur directed to solve a necessity, but haphazard - if it's beneficial there's an augmented chance it's passed on to the next generation. In this case, it looks like it's counter-productive, the extra glands consume resources to build but don't seem to give anything in return.
Traits related to white flower forms are often recessive. If the plant isn't sterile you could cross it with a normal form and check occurrence in selfed offspring (should be around 25%). If it's dominant than minimum 50% of the initial cross should carry it. But this assumes that it's expressed from a single gene.
What I find interesting is that they apparently lack mucus... Something you could do immediately is to cast a section in resin, slice it and compare a cross-section of these glands with a regular gland under the microscope. I don't know if you have access to this kind of equipment, but if there's a secondary school in your neighbourhood which has classes in woodcraft ... they also use this slicing technique to identify wood.
regards,
Fred
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Post by stevestewart on Dec 21, 2008 13:26:57 GMT
Fred & all, I am beginning to wonder what a "normal" form of Drosera indica looks like . I am sure Brian will get as much seed as he can from his interesting "white flowered" variety of D. indica. I am also looking forward to reading of Brian's and other growers (Jeremy!) results from attempted crosses of the unique D. indica varieties currently being grown. S. Hartmeyer stated in the thread I linked to, that D. hartmeyerorum and another Drosera in the Arachnopus group growing closely with it, cannot be hybridized. (Possibly it simply has not yet been done, or one variety is extremely dominant over the other genetically.  ) Having seen these plants myself, there is more than meets the eye in Brian's wonderful photographs, and these features need to be looked into thoroughly. ;D Sounds like fun to me! Take care, Steven Stewart |
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Post by Brian Barnes on Dec 21, 2008 13:40:46 GMT
Hey Fred, Steve and Dave.
Great advice indeed Fred...thanks! Actually, I contacted Siggi for his input (thanks, Siggi) and shall also be emailing a few pics to Allen Lowrie for his opinions on the matter as well. I'm very interested to see if the flowers truly are white and have blood-red, cobra shaped stamens. I have one that shall be opening any day now...I'll post some macro shots as soon as it is fully opened.
Another Drosera indica form I'm currently growing is the ("lime green to 20cm, honey scented plant", Howard Springs, Australia.)
It looks identical to the priorly discussed form, has an incredibly strong honey scent and a total lack of glandular appendages on the backs of the leaves. Hmmm....interesting. But so far, no signs of flowering as of yet...
Steve, I think we'll be able to drink quite a few pots of coffee over this one! ;D Now, if Santa would bring me a microscope, all would be fine and dandy! My 30X magnification just is not enough (combined with my failing eyesight!)
Thanks for the input everyone and Happy Growing,
Brian.
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Post by andreasfleischmann on Dec 21, 2008 17:19:57 GMT
Dear Brian, So you got interested in microgland features of Drosera indica as well . Welcome on board! . These (mostly Y-shaped) glands on the abaxial leaf surface are common in some "forms" of D. indica: more exactly in those with laterally emerging scapes, distinct non glandular petioles, large roundish seeds and widened connectives of the anthers (what looks "cobra-like" in some plants). That's mainly plants from northern Queensland (white flowers, narrow connectives) and N.T. (the cobra-stamen plants). I have observed either these dark red conspicuous glands in some plants, or the same thing in yellowish-green in plants from different locations. Keep on reporting about your interesting observations, Andreas |
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Post by Brian Barnes on Dec 22, 2008 10:29:47 GMT
Hi Andreas, Thanks for the information and welcome!  Indeed, this phenomena is quite obsessive and perplexing. I'm glad I'm not the only one with the "sickness" ;D Have you come across any of these lovely plants during your wonderful botanical explorations "Down Under"? I'd love to see a few 'in situ'... Happy Growing to you, Brian. |
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fred
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Post by fred on Dec 22, 2008 21:47:34 GMT
Before I forget. I recently wrote a small article on Passiflora, where species produce yellow glands to fool Heliconius butterflies into believing the plant has already been visited by egg-laying females, and thus protects the plant from caterpillars. The yellow Drosera hartmeyerorum trichomes remind me of this, especially since they're typically located at the base of the leaves. Unfortunately the notion of Drosera making itself unattractive for insects is ... rediculous. This afternoon I was walking off my winter depression in a local bird sanctuary and came across a small population of Dipsacus fullonum remnants. Weedy as they may be I can never suppress the urge to stop for a few moments and inspect the plants. Dipsacus is an example of what's thought of as pre-adaptation in insectivory. As a short explanation for pre-adaptation, think of the emergence of flying insects: insects need a special apparatus (wings and such) to fly, but this takes a large number of evolutionary steps to develop. Pre-adaptation in this case could explain that wing-like structures were first developed for a completely different reason, which decreased the transition to development of flight. Back to the Dipsacus. Dipsacus creates a small pool of water around the stem by fusing opposing petioles, thus trapping harmfull insects. The plants have a way of trapping/drowning insects but don't really benefit from the nutritional value. But it does show us that insectivory doesn't need to be an "all in once" evolution, pre-adaptation offers an intermediary step (protecting the plant). The same thing happens in Passiflora foetida: the inflorescence is enveloped by sticky glands which either protect it, or make it easy to disperse the seeds as in Plumbago (see at the bottom of this page). Here's what I'm going at: we don't really have problems in finding examples of pseudo-insectivores that offer us a glimpse in how they might evolve into true insectivores. Is there a possibility that D. hartmeyerorum trichomes (or indica disfunctional glands) show us the reverse: pre-adaptive structures which led to insectivory, but had a different reason altogether? As a small footnote, this also happens in humans ... a lecture I visited recently showed photographs of infants born with gill slits, apparently it does happen every so often and the surgery to correct this is rather common and flawless. BTW, shouldn't it be D. hartmeyeror a ? regards, Fred |
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Post by andreasfleischmann on Dec 23, 2008 15:57:22 GMT
Hello Fred, No, these non-carnivorous glands on the back of the leaves in Drosera indica (and several other Drosera by the way!) are not an atavism (like gill slits in humans), as this would mean that the most "primitive" Drosera species would have had them, too. This is not the case: D. regia and D. arcturi (the most basal extant Drosera spp.) do only bear one kind of glands: the multicellular sticky glands (tentacles) with round heads common in the inner surface of the lamina of all Drosera species. Nothing else. No non-glandular hairs, no special microglands (like those of D. indica), no unifacial marginal glands ("snap tentacles" ). All those structures derived from the "basic type" glands (or non-glandular hairs). These non-glandular hairs are common on the backs of the leaves (and usually on the flower scapes, too!) of all "derived" Drosera species, and they can be either simple, non-glandular hairs, short-stalked glandular hairs, or these more advanced multicellular glands. From the flower scapes of some Drosera species (D. tomentosa or D. montana for example!) you can see how easy it is for those plants to switch from "normal" non-glandular hairs to short glands or vice versa. (The same is true for scales and feathers on the legs of birds!). Thus in my opinion, these strange glands in some Drosera species are in fact modified simple hairs, and not a reverse evolution of carnivorous leaf glands. No. The plant is dedicated to _the_ Hartmeyers (Siggi and Irmgard), that's the Latin suffix "-orum" (noun genetiv plural! ). All the best, Andreas |
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fred
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Post by fred on Dec 23, 2008 17:18:34 GMT
Thanks for elaborating, Adreas.
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Thanks for your input...
)
Indeed, this phenomena is quite obsessive and perplexing. I'm glad I'm not the only one with the "sickness" ;D
