Thursday, March 30, 2023

Accidental Epiphytic Beauty

Cenchrus setaceus

In December 2020, I discovered a grass that was perched between two large branches of a tree.

This made me start thinking about why the Poaceae, even though it's the 4th or 5th most speciose plant family, did not really have real epiphytic species. I discussed this mystery in that old post, and came to the conclusion that it probably has to do with the fact that grasses are creatures of the light and wind. True epiphytes are pretty much all animal pollinated, and tend to occur in forested areas.

But "accidental" grass epiphytes do occur, and I came upon an instance of this again when strolling around a neighborhood and canvassing the many ornamental grasses that graced its grounds.

Cenchrus setaceus inflorescence (white stigma and yellow anthers)

Varieties of Cenchrus setaceus (subfamily Panicoideae) were in evidence everywhere. They have beautiful cylindrical flowerheads that are tinged with purple, and I was gazing at a group of the ornamental C4 grasses when I was astonished to find that two of the specimens were literally growing from the trunk of nearby palm trees! Not only that, but both had flowerheads rising from their tops, a testament to the tenacity of the individuals.

Flowering accidental epiphyte (red arrow points to base of grass)

I examined one of them (see image below), and found that the shoots of the grass emerged from what I think are balls of moss that had adhered to the trunk. The moss piece felt hard to the touch and crumbled slightly when I handled it. So it is possible that seeds from this species had landed on the moss, and had been able to grow to maturity in such an unusual location.

Rooted in moss (Cenchrus setaceus)

Although Florida is considered a humid area, it does have a dry season when rain does not occur for many days or even weeks on end. But the air must retain enough moisture that allows not only mosses to survive on the exposed palm trees, but other more complex plants as well, such as the ferns and Tillandsia "air plants" that decorate many of the tree limbs here. In addition, this is a suburban community, and I have a feeling the various underground sprinklers that dot the landscape contribute some water as well. Finally, this species has been known to become invasive, and thus might possess some rugged attributes that belie its graceful appearance and allow it to colonize inhospitable locations.

But whatever the reason for their growth and survival, the two C. setaceus specimens certainly prove that the Poaceae might not have many true epiphytes, but it's not because of lack of trying.  

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