Someone - I fear that I have lost the quote - asked about these two Dendrobiums. I am sure that there are details of flower morphology which set them apart, but the key distinction is in their general habit, habitat and growth patterns.
D. transparens occurs in many forms, merging into 'species' such as D. amoenum. I have seen mature plants with pseudobulbs three metres long intermixed with others that are plainly mature at 8cm. These are always whiplike, cylindrical and never more than 5 mm in diameter. The nodes are not prominent on old pseudobulbs, unlike those of D, nobile, and the leaves are fien textured, lanceolate and quick to fall in Autumn. Flowers vary from little more than a centimetre across to the more normal 3 cm. Colour ranges from white through blush pink to the 'normal' crystaline white with magenta blotches. All grow at around 1500m in relatively shaded habitats, usually horizontal branches of large trees, where they form beards, but also in shrubberies, often in association with Coelogyne, Otochilus and Pholidota species. D. nobile is highly distinct and does not merge with related species. It has somewhat flattened pseudobulbs that carry their leaves for several years. The leaves are leathery and oblanceolate, leaving prominent nodes when they fall. Old plants get a tufted look, as the pseudobulbs are carried for many years, remaining erect. This species is prone to throwing keikis, so old plants in nature can become extremely tangled. (And much beloved of 15cm centipedes.) D. nobile grows far lower - and therefore in a far hotter environment - than do the thin-cane species, such as D. transparens. (A typical range in the Himalayas would be 400-1000m). It flourishes on old tree trunks in full sun exposure, and I have never seen it in shady situation. It is often found near D. thyrsiflorum and D. densiflorum, which will grow on abandoned ladders, rocks and anything that presents itself. Lower still, one finds the hot-growing thing canes, such as D. primulinum and D. aphyllum, D. lituiflorum and so on. Higher up, the negrohirsutes begin, often flowering in damp, frosty conditions whilst their low altitude cousins cook at 45C in complete drought. The low altitude plants are easy to cultivate if one gives then an absolute dry period in Winter. The higher range plants are far more difficult to keep happy under glass house conditions, and I am told that they seldom flourish even when moved to Kathmandu, at intermediate altitudes. ______________________________ Oliver Sparrow +44 (0)20 7736 9716 www.chforum.org _______________________________________________ the OrchidGuide Digest (OGD) [email protected] http://orchidguide.com/mailman/listinfo/orchids_orchidguide.com
