Let me at this point my personal digression. Nature is extraordinary and without going far orchids let’s what to perpetuate the same species have machined a series worthy of the greatest strategist mechanisms. In effect orchids have no air pollen, vale say pollen what is transported by wind, resorted to an external auxiliary and attract bees, butterflies, flies, Hummingbird,. These animals attracted by shapes and diverse colors come into its complex floral structure and involuntarily transporting pollen from one flower to another. Some varieties of orchids are specific pollinating insects so you have structured its ad hoc flower by those particular energy.
A striking example is represented by the Orchid Angraecum sesquipedale, what possesses a long labello of more than 30 cm and the nectar found in the final part. This feature already was noticed by C. Darwin to hipotizo the existence of an insect what had a very long tube to reach the nectar. The good Darwin was right, in effect more than forty years later it was discovered that a butterfly had just the particularity of having a horn (proboscis) so long that it was named Xanthopan morganii praedicta (= predicted) in honor of the genius of Darwin. SHANK shank or stem, in the plant have both function of sustaining plant, as unite roots and flower to ensure a constant in both flow directions. There are orchids with shank and orchids without shaft.
Among the ORCHIDS with FUSTE we remember Cattleya, Dendrobium, Phalenopsis, Vanda, Oncidium. Among the ORCHIDS without shaft recall Phaphiopedilum, Pleurothallis and Masdevallia, etc at the same time orchids can have the stem which unfolds: with growth VERTICAL called monopodial (examples are Phalaenopsis, Vanda, Angraecum) with a single stem which grows upright and has no pseudobulbs. The flowers grow near the Apex between the leaves. WITH HORIZONTAL growth call simpoidal (examples are Cimbidium, Dendrobium, Cattleya, etc) have a sort of Rhizome that grows horizontally in vertical stems which sprout called pseudobulbs.