Nick Plummer wrote: "what do we call a shoot that bears only a keiki? Does "adventitious shoot" refer just to the keiki, or does it encompass the keiki and the shoot that bears it?"
I would use the term "adventitious shoot" to refer to any shoot produced by a self-supporting plant that has the potential to develop into a separate, self-supporting entity. Thus the keikei is an adventitious shoot, but the inflorescence-like organ that supports it would be a stem. "In the Taeniophyllum, was the shoot bearing the keiki longer and growing at a different angle than an inflorescence?" It was several times longer than the old inflorescence-remnants on the mother plant. However, since the Taeniophyllum species involved has not been identified, it cannot be stated with certainty that the keikei-bearing shoot was any longer than an average inflorescence from this species. The productive inflorescence on the keikei was abnormally small. Inflorescence angle in Taeniophyllum isn't a very meaningful line of pursuit since most species don't seem particularly geotropic and will happily grow right-way up, sideways, or upside down. In the bark-hugging species the inflorescences grow outwards away from the stem axis, and you are likely to find them going upwards, sideways or downwards with respect to gravity. In the species that hang by their root tips, the plant's main concern seems to be to get the flowers outside the root-ball, without bothering about the subtleties of "up" and "down". The Taeniophyllum that I was talking about is a bark-hugger, and I saw nothing unusual about the angle. I have no problem with a Dendrophylax producing a specialist stem whose only function is to produce keikeis. Lots of other orchids do it. Phalaenopsis do it from barren inflorescence-like shoots. If you check pages 340-341 of my "Lowland Orchids of PNG" book, you'll see a description of an un-named Dendrobium species in section Grastidium which propagates by producing adventitious shoots along specialist scrambling rhizomes, in the same way that grasses and strawberries reproduce vegetatively by sending out stolons. Since I wrote the book, I've seen the same thing in several other Dendrobiinae. This is, essentially, the same thing that you saw in Dendrophylax. If it works, there will be an orchid somewhere that does it. Cheers, Peter O'Byrne in Singapore _______________________________________________ the OrchidGuide Digest (OGD) [email protected] http://orchidguide.com/mailman/listinfo/orchids_orchidguide.com
