Climbing with aerial rootlets

A comment and response in the previous post mentioned that poison ivy can grow as a vine. To make that clearer, here’s a picture from January 19, 2012, of two poison ivy vines that had climbed a tree in a wooded part of Great Hills Park. The aerial (as opposed to underground) rootlets that poison ivy uses to attach itself to a tree can be a warning sign to people who might otherwise innocently touch or lean against a tree like this one. The second word in the scientific name Toxicodendron radicans means ‘rooting,’ and now you see why that word was chosen.

© 2012 Steven Schwartzman

Two-fruit panorama

Click for greater clarity and considerably larger size.

The little red fruits scattered throughout are on a possumhaw tree, Ilex decidua, which hadn’t yet lost its leaves. The clusters of little off-white fruits in the left half of the picture (you’ll probably have to click the image to enlarge it) are from poison ivy, Toxicodendron radicans. At the far right of the photograph, the leaflets beginning to turn reddish atop a brown stalk are also poison ivy. Few people like this species, but you have to give it credit for versatility: it can grow as a low plant, a stalk, a bush, or even a vine that can climb tall tree trunks. I don’t know how an individual poison ivy plant “decides” which form to take.

Date: November 26. Place: near Bull Creek in northwest Austin.

© 2012 Steven Schwartzman