Annual (or perennial?) herbs, with large long-petioled basal leaves, erect simple scapes and terminal panicled spikes of bracted usually purple flowers. Sepals 3, membranous, separate, equal. Petals 3, separate or somewhat coherent at the base. Staminodia slightly united below, one of them (labellum) broad, crested. Anther i-celled. Ovary 1-celled or with 2 additional small empty cavities. Base of the style adnate to the base of the stamen-tube. Stigma 2-lipped, dorsally appendaged. Capsule globose of ovoid. Seed erect. Embryo strongly curved. [In honor of Johann Thalius, German naturalist of the sixteenth century.]

About 7 species, all American. Besides the following, another occurs in the southern States. Type species: Thalia geniculata L.

1. Thalia Dealbata Roscoe. Powdery Thalia. Fig- I352

Thalia dealbata Roscoe, Trans. Linn. Soc. 8: 340. 1807.

Plant finely white-powdery nearly all over. Scapes rather stout, terete, 3°-6° tall; petioles \°-2\° long, terete; leaves ovate-lanceolate, acute or acuminate at the apex, rounded, narrowed or subcordate at the base, 1/2°-1° long, 3'- 5' wide; panicle 8'-18' long, its spikes numerous, usually erect or ascending; bracts of the panicle narrow, deciduous, not longer than the spikes; bractlets ovate, unequal, coriaceous, about ¥ long; flowers purple, longer than the bractlets; capsule ovoid, about 4" in diameter.

In ponds and swamps, South Carolina to Louisiana, Missouri and Texas.