TRELEASBA, A NEW GENUS OF COMMELINACEAE. 



By J.N. Rose. 



Treleasea Rose, gen. nov. 



Sepals distinct, concave, Bttbequal, greenish or scarious. Petals distinct, tapering 

 at base into a slender claw, cohering and forming a slender tube. Stamens C, all 

 perfect, subequal, more or loss hairy, borne on the petals. Style slender, 3-lobed. 

 Capsule stipitate, 3-celled. Cells dehiscent, 2-seeded. Perennial herbs from tuber- 

 ous roots. Cymes sessile, many-flowered, either in terminal or axillary clusters. 



This name is given in honor of Dr. William Trelease, director of the Missouri 

 Hotanical Garden, whose well known services to botany and horticulture deserve 

 this recognition. 



This genus differs from Tradescantia, especially in the corolla and the position of 

 the stamens. Tradescantia has always an open flower spreading from the base, with 

 petals broad at base, while Treleasea has the petals tapering into a claw, forming a 

 tube and only spreading toward the top. The stamens, too, are always free in 

 Tradescantia, while in Treleasea they are borne on the petals. 



The genus seems nearer Cyanotis than Tradescantia, hut differs from that in 

 its stipitate fruit, concave sepals, etc. It is perhaps nearest Zebrina, differing 

 chiefly in the fact that the petals are not united into a tube, but merely cohere at 

 the edges. 



I have long been dissatisfied with the reforence of the species brevifolia to Trades- 

 cantia, having had the plant under cultivation since 1895. Whilo in Mexico in 

 1897 I found another plant of similar habit with the same flower structure, show- 

 ing that this is a good generic type. T. leiandra, although the Ilower structure is 

 doubtful, possesses the stipitate fruit and otherwise suggests that it belongs hero 

 also. 



The genus, as I now understand it, consists of the three following species, of 

 which brevifolia is the type : 



Treleasea brevifolia (Torr.) Rose, nom. nov. Tradescantia { t) brerifolla Rose, Contr. 

 Nat. Herb. 3 : 323. 1895. Tradescantia leiandra brevifolia Torr. Bot. Mex. Bound. 

 225. 1859. T. speciosa Buckley, Proc. Acad. Phila. 1862 : 9. 1863. Not L. or 

 H. B. K. Zebrina (?) leiandra Clark, in DC. Monogr. Phan. 3 :318. 1881. 7*. 

 leiandra Wats. Proc. Am. Acad. 18:167. 1883. Not Torr. Same, Hemsley, Biol. 

 Centr. Am. 3:393. 1885. 2'. leiandra ovata Coulter, Contr. Nat. Herb. 1:50. 

 1890. Same, 1. c, 2:444. 1894. 



Steins prostrate, leafy to the top; leaves approximate, ovate, 2.5 to 7.5 cm. long, 

 2.5 cm. wide, thickish, glaucous and glabrous, except the ciliate-scabrons margins, 

 acute; margin of sheath ciliate; involucral leaves 2, like the lower leaves, but 

 smaller; umbel sessile, many-flowered; corolla white, petals ovate, obtuse, some- 

 what spreading, tapering at base into a slender claw, stamens erect, longer than the 

 petals, hairy near the middle, attached to petals; ovary hairy near the top. 



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