Monday, May 18, 2009

Mega-rare Vegetable Matter

After spending an enjoyable Sunday morning in the Oak Openings with lots of attendees from the Ohio Ornithological Society conference, I had the opportunity to mine a botanical treasure trove. Eric Durbin, naturalist and Oak Openings authority, agreed to take me to see two of the rarest plants in the state. I was sworn to secrecy and threatened with severe flogging if I revealed any locational data, so I won’t. But I did my best to document the plants with photos, and I hope you enjoy them. And I very much appreciate Eric taking me to see them, and for sharing some of his wealth of knowledge about the Oak Openings.

Tiny – really tiny – but incomparable. This is Fringed Milkwort, Polygala paucifolia, an endangered species known from but a few Ohio locales. It forms small colonies, and this patch covered only a few square inches. The plants grow low and flat, basically hugging the ground, and it’d be easy to pass by.

Upon close inspection, this milkwort is a thing of beauty. Too bad it is so rare in our state. Travel further north, and it abounds. Mean average soil temperature may be one of the factors limiting its southward extent, with extreme northern Ohio barely cool enough for it to tolerate. The large pink dumbo ear-like projections are actually colored bracts, or modified leaves – not the flowers.

This minute tube is the petaliferous part of the plant. The flower is waning, but a Fringed Milkwort in peak bloom somewhat suggests the appearance of an airplane, with the petals being the rotor and the trailing bracts as the wings. It was once believed that consumption of milkworts would stimulate milk production in both cows and human mothers, hence the odd name.

A major find, and a life plant for me. This one is Long-bracted Orchid, Coeloglossum viride, another state-endangered species. Having now seen this site, I can attest that Durbin really found a proverbial needle in a haystack here. There is but one plant, and it is in the dense gloom of thick understory and not easy to see.

We have forty-six native orchids in Ohio, and most are not overtly showy as are many of the tropical, cultivated species. Still, our plain janes have their charms – to some of us, these more obscure northern orchids are more charismatic than some of their gaudy brethren.

Coeloglossum (See-lo-gloss-um) is sometimes known as the “frog orchid”. This colloquialism apparently stems from the fanciful resemblance of the flowers to certain amphibious hoppers. The origin of Long-bracted Orchid isn’t hard to determine: those long leaflike structures subtending the flowers are bracts, and they are long.

All orchids have interesting flower structures, and this one is no exception. Note the small beetle going, presumably, after pollen on the middle left flower. I always get very curious about pollinating insects on these rarities. Very little work has been done on the relationship of plants and insects and the intimate role that the latter play in pollination.

Long-bracted Orchid has an expansive range throughout northern North America and Eurasia. It is not rare in the core of its range. Like the milkwort, Ohio is at the southern limits of its distribution. Northern species such as this bear watching. Warming climate and subsequent increases in mean average soil temperatures would, theoretically, cause these species to retreat northward.

Thanks again to Eric for sharing these jewels.

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