538 MAYACE^E. (MAYACA FAMILY.) 



1. MAYACA, Aublet. 



The only genus. Perianth persistent, of 3 herbaceous lanceolate sepals, 

 and 3 obovate petals. Stamens alternate with the petals. Ovary with 3 pari- 

 etal few-ovuled placentae ; style filiform ; stigma simple. Creeping or float- 

 ing in shallow water ; the leaves 1-nerved, entire, notched at the apex ; the 

 peduncle solitary, sheathed at base. (An aboriginal name.) 



1. M. Michauxii, Schott & Endl. Peduncles not much exceeding the 

 leaves, nodding in fruit. Va. to Fla. and Tex. 



ORDER 120. COMMELINACEJE. (SPIDERWOKT FAMILY.) 



Herbs, with fibrous or sometimes thickened roots, jointed and often branch- 

 ing leafy stems, and chiefly perfect and 6-androux, often irregular flowers, 

 with the perianth free from the 2 - 3-celled ovary, and having a distinct 

 calyx and corolla ; viz., 3 persistent commonly herbaceous sepals, and 

 3 petals, ephemeral, decaying or deciduous. Stamens hypogynous, some 

 of them often sterile; anthers with 2 separated cells. Style 1; stigma 

 undivided. Capsule 2 - 3-celled, 2 - 3-valved, loculicidal, 3 - several- 

 seeded. Seeds orthotropous. Embryo small, pulley-shaped, partly sunk 

 in a shallow depression at the apex of the albumen. Leaves ovate, 

 lanceolate or linear, parallel-veined, flat, sheathed at base ; the upper- 

 most often dissimilar and forming a kind of spathe. Chiefly tropical. 



1. Commelitia. Cyme sessile within a cordate or connate bract (spathe). Petals un- 



equal. Perfect stamens 3 ; filaments naked. 



2. Tradescantia. Bracts leaf-like or small and scarious. Petals equal. Perfect stamens 



6 ; filaments bearded. 



1. COMMELINA, Dill. DAY-FLOWER. 



Flowers irregular. Sepals somewhat colored, unequal ; the 2 lateral partly 

 united by their contiguous margins. Two lateral petals rounded or kidney- 

 shaped, on long claws, the odd one smaller. Stamens unequal, 3 of them fer- 

 tile, one of which is bent inward ; 3 of them sterile and smaller, with imperfect 

 cross-shaped anthers ; filaments naked. Capsule 3-celled, two of the cells 2- 

 seeded, the other 1 -seeded or abortive. Stems branching, often procumbent 

 and rooting at the joints. Leaves contracted at base into sheathing petioles ; 

 the floral one heart-shaped and clasping, folded together or hooded, forming 

 a spathe enclosing the flowers, which expand for a single morning and are 

 recurved on their pedicel before and afterwards. Petals blue. Flowering all 

 summer. Ours all with perennial roots, or propagating by striking root from 

 the joints. (Dedicated to the early Dutch botanists .7. and G. Commelin.) 



* Ventral cells 2-ovuled (usually 2-seeded), the dorsal 1-ovuled. 



1. C. nudifldra, L. Slender and creeping, glabrous; leaves lanceolate, 

 small (1-2' long); spathe cordate, acute, with mart/ins not united; seeds re- 

 ticulated. (C. Cayenneusis, Richard.) Alluvial banks, Del. to Fla., west to 

 Ind., Mo. and Tex. 



2. C. hirtella, Vahl. Stout, erect (2-4 high) ; leaves large, lanceolate, 

 the sheaths brown-bearded ; spathes crowded, with margins united ; seeds smooth. 



