Sunday, July 29, 2012

Around the Garden

A Tree Blooms in Middletown

The urge to put a name on every plant seems ingrained in gardeners. Sadly, not everyone has – or wants – access to botanical names, so a vast array of common names has grown up around plant life. Sadly, because those names vary from one place to another, often creating great confusion.

Some find political implications in this: Jamaica Kincaid, in one of her gardening diatribes, accuses plant collectors of Colonialism and worse, for renaming tropical plants. It is certainly true that many of us feel an increased sense of ownership when we can call up the correct name for a plant growing in our gardens.

Trees can present special problems, especially when tall and mature. A primary source of identification is the arrangement of buds and leaves on twigs and branches. Often, the tree in question is so tall that it takes a keen eye, or very good binoculars, to figure out what is growing where.

I recently came across an extremely puzzling tree on one of my rambles through Middletown’s backyards. Luckily, these trees were only about 10 feet tall, and their leaves were easily reached, but they were like no other leaves I had seen. Large and heart-shaped, they grew on reddish petioles in alternate arrangement on the twigs. The bark was pale gray and heavily lenticeled. Some trees had single stems, some were in clumps of three.

Totally stumped (as it were) I took some leaf cuttings, in addition to digital photos and spent a few hours paging through my little library to no avail.

Knowing my limitations, I emailed my pictures and a description to the indisputable tree expert in these parts: Ed Richardson of the CT Botanical Society. Ed identifies and measures trees for the CT Notable Tree list, so he almost always can come up with an identification. Doing this from photographs, of course, is much harder than doing it in the field. The feel of a leaf, the hairs on the underside or stem, minute “teeth” on the edge, the gradations of color – all can make identification much faster.

But even working with so-so photos, Ed was more successful than I.
A few hours after I sent the pictures, Ed was on the phone, saying he thought he had it. Page 500 of The Book of Leaves, he said – and I went straight to my copy. And even though I had spent hours with this book, Ed had found what I missed: Poliothyrsis sinensis!

From there, we went to Michael Dirr’s Manual of Woody Plants, where the most recent edition lists this oddity, and the fact that it had been propagated at the Arnold Arboretum. Bingo – the homeowner said her brother had grown the trees from seeds he had gotten at the Arnold.

On to the Internet, where we found a an article in Arnoldia, the magazine of the Arnold Arboretum, which gave a much fuller description of the tree, including the news that this tree grew in Boston from 1908 to 1933, and then disappeared, only to be reintroduced with seed shipped from Shanghai in 1981.

Two other web sites identified Poliothyrsis variously as the Pearl-bloom tree or the Chinese Pearlbloom tree. The flowers, which opened up last week, explain the common name: each panicle consists of dozens of tiny, round flowers, in shades from white to a sort of old-pearl ivory.

Parsing the botanical name is more of a challenge. The “sinensis” part is easy – Latin for Chinese. The “Polio” prefix means gray, and certainly the bark is gray. Then comes the “thyrsis” – and whether the quotation is from Matthew Arnold, Vergil or Theocritus, Thyrsis is always a shepherd. But, lo – one botanical dictionary contains “thyrse” which it defines as a flowering panicle or inflorescence.

So, we have a Chinese tree with gray bark and flowers that resemble a lilac’s bloom. Maybe it was poetic license to turn “thyrse” into “thyrsis” or maybe that’s the plural of thyrse. Chinese Pearlbloom tree? I’ll go with the common name this time.

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