The Carnivorous Plant FAQ v. 12

Q: Philcoxia: the nematode plant

A: Philcoxia is the most recent carnivorous plant genus to have been discovered. In basic strategy, it is a sticky-leaved plant. On the other hand, it has a little trick up its sleeve.

If you were lucky enough to encounter this plant in Brazil (and very few people have!), you would no doubt only notice the short (up to about 25 cm tall), branching inflorescences. The small flowers (pink, or pale blue to lilac, perhaps with a bit of yellow) are bilaterally symmetric, lack spurs, and have 5 lobes.

The plant's leaves are entirely underground--just barely hidden under the sandy soil crust. The leaves emerge from the underground stem, and are placed at the end of long, filamentary petioles. Each leaf is round, to slightly elongated, and covered (on the upper surface) with short-stalked glands. In one species (P. bahiensis) not only are the glands found on parts of the lower leaf surface, but also sessile glands are seen.

Laboratory and greenhouse work convincingly demonstrates that these leaves attract and kill nematodes. Furthermore, the leaves digest the nematodes and absorb the nutrients. While this work has only been completed for P. minensis, I would not be surprised if the entire genus turns out to be carnivorous.

This is--so far--the only carnivorous plant that seems to specialize in nematodes--although nematodes have been observed being killed and eaten by other carnivorous plants. Also, it has been noted that this is the only sticky-leaved carnivorous plant that hunts under the sand. However, I'd like to point out that Drosera zonaria is often partly or completely buried in the sand.

The genus is named after David Philcox, a Kew botanist that worked on tropical Scrophulariaceae. Three of the species are named after the state in which they were first found (Bahia, Goiás, and Minas Gerais). There are no common names for these plants.

Page citations: Fritsch, P.W., et al. 2007; Pereira, C.G., et al. 2012; Pereira, C.G. and Oliveira, R.S. 2010; Taylor, P., et al. 2000.

back forward


Revised: 2018
©Barry Rice, 2018