TKIANDRIA. MONOGTNIA. ^t 



^ire, narrow, sessile, and linear; peduncles all axillary, a 

 little pubescent; involucrum 3-flowered. 



Obs. Perhaps only a variety of the preceding; still it 

 preserves the same habit under cultivation; the stems come 

 up several from tiie same perennial root, always inclining 

 to be decumbent, not above 6 inches high, the preced- 

 ing 2 feet; flowers axillary, peduncles short; leaves rather 

 thick, without veins, not more than 2 lines wide and 2 

 inches long, perfectl)'^ smooth and rather obtuse; flowers 

 very small, pale red, and so evanescent as rarely to be 

 seen open. Fruit and involucrum as in the other species. 

 On high, bare, gravelly hills near Fort Mandan, on the 

 Missouri. Flowers in June and July. 



Tills genus, now contain ng about 13 species, is 

 thus far confined to Peru, New Spain, and tlie United 

 States, being-cntireiy an American genus. There ap- 

 pears to be but one species of Calvmenia in New Spain, 

 the C. agg-regata, liaving more than a single flower in 

 the involucrum, while in the United States, in all the 

 species it produces tlu-ee or more flowejs. The cali- 

 cine, peltate involucrum, the deep emarglnation of tlie 

 5 divisions of the corolla, and the absence of theminute 

 marginal calix, are apparently all the essential generic 

 distinctions subsisting between the Cali/tnenia and JBoer- 

 haavia. 



Iff Flowers inferior, 



). COMMELINA. L. 



Calix 3-leaved. Corolla Spetalled, mostly 

 unequal. /S'^ami7ia 6, sometimes all fertile, but 

 for the most part 3 or 4 are sterile. Stigma 

 simple. Capsule, sub-globose, 3-cellecl, 3-valv- 

 ed, 2 of the cells 2-seeded, the third with its 

 proper valve, often abortive. 



Stem herbaceous, and often branching; leaves almost 

 gramineous, alternating at the nodes of the stem, the 

 sheath of the leaveslongand entire, nearly cleft; branches 

 sheathed at the base; peduncles axillary or terminal, one 

 or many flowered; spatha cordate, persistent, closing and 

 enveloping the flowers; rarely wanting. 



Species. 1. comimmis. 2- erecta. 3. Idvtella. 4. Virgi- 

 nica. 



Obs. The genus Commelina^ with the exception of the 

 species in the United States, and 2 others in Japan* is pe- 

 culiar to the tropical regions of India and America: tliere 



