Top:
Oncidium excavatum
Bottom:
Phalaenopsis philippinensis
42.150987, -71.383086
The Onc. and Phal. are epiphytes. The specialized adaptation of both plants is that they both have vellamen tissue thickly coating their thin, wiry roots. The vellamen tissue absorbs ambient moisture, but also soaks up rain. Another adaptation is that, as epiphytes, these plants need to get nutrients from somewhere other than soil. Many growers believe that they can derive most nutrition from the sun and air, but the air doesn't contain much inorganic phosphorous, bioavailable nitrogen, or potassium ions! The leaves, therefore, despite being devoid of trichomes, are effective are absorbing and storing nutrients. Phals have large, thick leaves that do this job, but look at the Onc. Its leaves are thin, so it has a specialized stem, called a psuedobulb, which holds moisture so that the plant can go months without rain (as long as the humidity stays fairly high) during its winter dormant period.
You might think that the phal is planted upside down. Indeed, this is not true! The way it is growing is actually pendulous, it's version of right-side-up. This adaptation helps prevent crown rot, an affliction Phals are susceptible to due to their absorbent leaves and monopodial growth habit. This raceme will grow upwards, so at least the grocery stores manage to get that right.
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