C0MMEL1NA CEA E. 239 



of the seventeenth century.] About 350 species, natives of warm and tropical 

 America. Besides the following some 9 others occur in the southern U. S. 



x. Tillandsia usneoides L. Long Moss. Florida Moss. (I. F, f. 904.) 

 Stems very slender, thread-like, flexuous, hanging clustered in festoons from the 

 branches of trees, 1-8 m. long, gray and, like the filiform leaves, densely silvery- 

 scurfy all over. Leaves scattered, 2-8 cm. long, scarcely 1 mm. thick, their bases 

 somewhat dilated ; flowers sessile and solitary or rarely 2 together in the axils of 

 the leaves ; sepals about 6 mm. long, pale green ; petals yellow; stamens about as 

 long as the calyx ; capsule linear, 2-3 cm. long, at length splitting into 3 linear 

 valves. E. Va. to Fla., Tex. and Mex. Very widely distributed in tropical 

 America. 



Family 5. COMMELINACEAE Reichenb. 



Spiderwort Family. 



Perennial or annual leafy herbs with regular or irregular perfect and 

 often showy flowers in cymes, commonly subtended by spathe-like or leafy 

 bracts. Perianth of 2 series ; a calyx of mostly 3 persistent sepals and a 

 corolla of mostly 3 membranous and deciduous or fugacious petals. 

 Stamens mostly 6, hypogynous, rarely fewer, all similar and perfect or 2 

 or 3 of them different from the others and sterile ; filaments filiform or 

 somewhat flattened ; anthers 2-celled, mostly longitudinally dehiscent. 

 Ovary superior, sessile or very nearly so, 2-3-celled ; ovules 1 or several 

 in each cell, anatropous or half anatropous ; style simple ; stigmas termi- 

 nal, entire or obscurely 2-3-lobed. Seeds solitary or several in each cell 

 of the capsule. Capsule 2-3-celled, loculicidally 2-3-valved. Embryo 

 small. Endosperm copious. About 25 genera and 350 species, mostly 

 natives of tropical regions, a few in the temperate zones. 



Perfect stamens 3, rarely 2 ; petals unequal ; bracts spathe-like. 1. Commelina. 



Perfect stamens 6, rarely 5 ; petals all alike ; bracts leaf-like. 2. Tradescantia. 



1. COMMELINA L. 



Somewhat succulent, branching herbs, with short-petioled or sessile leaves, and 

 irregular mostly blue flowers in sessile cymes subtended by spathe-like bracts. 

 Sepals unequal, the larger ones sometimes slightly united. Petals unequal, 2 of 

 them larger than the third. Perfect stamens 3, rarely 2, one of them incurved 

 and its anther commonly larger. Sterile stamens usually 3, smaller, their anthers 

 various. Filaments all glabrous. Capsule 3 -celled. Seeds 1 or 2 in each cavity, 

 the testa roughened, smooth or reticulated. [Dedicated to Kaspar Commelin, 

 1667-1731, Dutch botanist.] About 95 species of wide distribution in warm and 

 temperate regions. Besides the following, some 5 others occur in the southern U. S. 



Spathes not united at the base. 



Spathes acuminate; capsules 3-celled, 5-seeded. 1. C. nudiflora. 



Spathes acute ; capsules 2-celled, 4-seeded. 2. C. communis. 



Spathes with united bases. 



All three cavities of the ovary with 2 ovules. 



Sheaths, at least the lower ones, glabrous or nearly so; pubescence, if present, not 



hirsute. 3. C. crispa. 



Sheaths more or less hirsute. 



Capsules 2-valved, dorsal cavity indehiscent. 4. C. Virginica. 



Capsules 3-valved, all cavities dehiscent. 5. C. erecta. 



Ventral cavities of the ovary with 2 ovules, dorsal cavity with 1 ovule. 



6. C. hirtella. 



I. Commelina nudiflora L. Creeping Day-flower. (I. F. f. 905.) Glabrous 

 or very nearly so; stems procumbent or creeping, 3-8 dm. long. Leaves lanceolate 

 or ovate-lanceolate, 2.5-7.5 cm. long, acute or acuminate at the apex, their sheaths 

 sometimes ciliate ; spathe acuminate, 2-4 cm. long, peduncled, the 2 bracts not 

 united by their margins ; flowers few in each spathe, 6-12 mm. broad ; ventral 

 cavities of the ovary 2-ovuled, the dorsal i-ovuled ; capsule commonly 5-seeded 



