Arizona Xerophytes

I do like the word xerophyte, along with its adjectival form xerophytic. The words begin with x’s and are pronounced as if they began with z’s. What’s not to like?

The words come from Greek roots meaning “dry”and “plant”. A related word, xerophilous, literally means something like “liking dryness”. The word is an adjective used to describe desert plants; a less anthropomorphic and more scientific definition might be “tolerating dryness”.

My experiences finding ferns in Missouri and Illinois didn’t prepare me for the xerophilous ferns I’ve been finding here in Southeast Arizona. Most ferns in the Midwest tend to live in humid environments, clustered around spring seeps and near streams. I didn’t expect to find ferns among the agaves and cacti.

The first fern I identified along the nearby canyon slopes was Cheilanthes lindheimerii, a common denizen which lurks around the edges of granite outcroppings. The ferns are also known as “Fairy Swords”, and you can see some photos in this earlier post:

Fairy Swords

Here’s a shot of a swarm of these flowerless plants taken some weeks later:

March Swords

A couple of days ago I happened across a clump of another species of fern, one I’d seen before a few weeks ago. Unfortunately I had completely forgotten just where the clump of ferns was located and several fruitless searches during walks had stymied me. Not a big deal, but I knew the ferns were out there and I was fairly certain that the plants had remained immobile. One reason I gravitate towards plants and fungi is that they tend to stay in one place, without that annoying tendency birds and mammals have of fleeing.

The Cochise Cloak Fern (Astrolepis cochinensis) is a beautiful organism, with its rounded leaflets and arching growth habit. Here’s a patch growing in front of a granite outcrop:

It interests me that two very similar subspecies have been identified; this one, subspecies arizonica, grows on weathered granite or feldspar-rich volcanics, while another form, subspecies cochisensis, grows among limestone outcrops.

A closer view:

I’m very fond of the gray-green hues of these ferns; the greens are muted by growths of tiny white hairs, some star-shaped, which I suspect help to shield the green tissues from the sun’s fierce summer rays.



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Filed under Arizona, Essays and Articles, Natural History, Photos

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