Liberal Arts Blog — Orchids II: Epiphytes vs Terrestrials, Wide Distribution, Ancient History
Liberal Arts Blog — Wednesday is the Joy of Science, Engineering, and Technology Day
Today’s Topic — Orchids II: Epiphytes vs Terrestrials, Wide Distribution, Ancient History
Last time, the anatomy of the orchid (sepals, pedals, column, and lip) and a little cultural history (the national flower of multiple countries). Today, a few notes related to three remarkable facts. First, 70% of orchids are epiphytes, that is they live on other plants without being parasites. Second, orchids are among the oldest flowering plants on the planet — dating back over 100 million years. Third, distribution is extremely broad — all continents except Antartica. Experts — please chime in. Correct, elaborate, elucidate.
EPIPHYTES (70%) AND TERRESTRIALS — BUT NOT PARASITES
1. I was recently startled to see a gorgeous orchid growing out of a live oak tree in northern Florida and decided to do a little research and was shocked to learn that this is quite normal for orchids.
2. Epiphytes are not parasites in that they derive no nutrients from their hosts. Terrestrial orchids “grow on the ground, rooting in humus.” (first link)
3. “Typically, epiphytic orchids have prominent, succulent stems called pseudobulbs that enable them to endure dry periods. Their leaves may be thin and deciduous or leathery and persistent. Their root systems are not as extensive as those of terrestrial orchids but are highly efficient at quickly absorbing moisture and nutrients.”
NB: “Epiphytic orchids are largely confined to the tropics and subtropics, where day length and the aspect of the sun vary little with the seasons and temperature ranges are generally stable and above freezing. While almost any part of a tree can be host to epiphytic orchids, the largest number of orchid species prefer the inner branches and limbs of large, mature trees, midway up, in lightly shaded conditions. Certain tree species consistently harbor orchids. Rough-barked trees that allow some moisture to remain in the cracks and crevices tend to be more conducive to orchid growth than smooth-barked trees.”
ORCHIDS ARE ALMOST EVERYWHERE BUT CONCENTRATED IN THE TROPICS
1. “Orchids are found on all continents except Antarctica, from above the Arctic Circle in the north to Tierra del Fuego and Macquarie Island in the south. However, the vast majority of orchid species are native to the tropics, and their numbers increase with proximity to the equator.” (first link)
2. “Many orchid species are endemic, meaning they are found only in a very specific area, such as a particular mountain ridge, and nowhere else.”
3. “The richest diversity of orchid species is found in the lush tropical forests of equatorial South America, Southeast Asia, and New Guinea. New species are constantly being discovered, particularly in these areas.”
NB: Oceania: 50 to 70 genera; North America: 20 to 26 genera; tropical America: 212 to 250 genera; tropical Asia: 260 to 300 genera; tropical Africa: 230 to 270 genera: Europe and temperate Asia: 40 to 60 genera. (second link)
ORCHIDS ARE ANCIENT — OVER 100 MILLION YEARS OLD !!!!! (fourth link below)
1. The latest orchid “evolutionary timeline begins 112 million years ago, when the first orchids appeared. About 90 million years ago, the major living lineages started to split from each other.”
2. “Then, sometime before 64 million years ago, a key innovation occurred: Orchids developed a way to lump their pollen into sticky balls, called pollinia, so that pollinators would not lose any grains before reaching other orchids.”
3. “As flowers evolved intricate structures to attach pollinia — some orchids stick them smack between the eyes of their favorite insect species, for instance — reproductive barriers likely formed, giving birth to new species.”
NB: Darwin was obsessed with orchids. After penning On the Origin of Species, he followed up with a treatise on the pollination of orchids. “The contrivances for insect fertilization in Orchids are multiform & truly wonderful & beautiful.” (Darwin)
FOOTNOTES — THE DON’TS OF GROWING ORCHIDS (tenth link below)
1. Don’t water orchids from above.
2. Don’t leave water in the orchid pot.
3. Don’t water orchids with ice.
NB: How to grow orchids in a tree? See links 8 and 9 below.
A LINK TO THE LAST THREE YEARS OF POSTS ORGANIZED BY THEME:
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