1. Commelina L. Widow's-tears. Day-flower 



Plants herbaceous, annuals or perennials; stems at first erect, in some species 

 eventually decumbent; leaves ovate to linear, forming a sheath at the base, margin 

 of leaf and throat of sheath often lined with white or reddish trichomes; flower 

 buds borne inside of a cymbiform spathe that is open across the top, 3 to 5 buds 

 are produced in each spathe, the buds opening in succession 3 or 4 days apart; 

 flowers blue or sometimes paler, exserted above the spathe shortly after dawn 

 to remain until midday after which they recede into the spathe as a juicy mass; 

 sepals 3, one subequal to the other 2; petals 3, one of which is subequal to 

 the other 2 and often paler; stamens 3, the smaller staminodia 3; ovary 3- 

 carpellate; fruits usually 1 or 2 or sometimes 3 per spathe; seeds 1 to 3 per fruit. 



About 225 species, mainly in tropical and subtropical regions of both hemi- 

 spheres. 



1. Spathes open across the top but closed down the adaxial side, the margins 

 connate at base 1. C. virginica. 



1 . Spathes open across the top and down adaxial side to spathe stalk, the margins 



not connate at base (2) 



2(1). Two posterior petals blue; anterior petal much smaller, white, lanceolate; 



capsule 2-celled, 4-seeded (no rudiment of third cell); anthers 6 



2. C communis. 



2. All three petals blue; anterior petal ovate, slightly smaller; capsule 3-celled, 



5-seeded (posterior cell 1 -seeded, indehiscent) ; anthers 5 (posterior 

 lacking) 3. C. diffusa. 



1. Commelina virginica L. 



Plant perennial, overwintering by a tuberous root system, commonly producing 

 new plants by elongated prostrate rhizomes that turn up at the ends; stem erect 

 to decumbent, 3-6 mm. in diameter at base, the longest internodes usually 8-18 

 cm., leaves broadly lanceolate, when mature to 2 dm. long and 65 mm. wide, 

 finely pubescent, especially scabrous to the touch when rubbed from the tip toward 

 the base; leaf sheaths heavily pubescent at throat and down the open edge, the 

 hairs sandy-red to dark-red in color; spathes terminal and usually clustered, 

 occasionally produced singly at top, glabrous to very finely pubescent, to 35 mm. 

 long and 2 cm. high, closed down the adaxial side, open across the top, tapering 

 to a point on abaxial side. 



In low woods, about and in water of pools, in s.e. Okla. (Pushmataha Co.) and 

 in e. and n.-cen. Tex., May-Oct.; from e. Tex. and Okla., n. to 111. and Md., e. to 

 the Atl. Ocean. 



2. Commelina communis L. 



Plant annual, with a fibrous root system, to 5 dm. tall; stems erect at first, 

 later becoming prostrate and spreading due to numerous branches being produced, 

 to 4 mm. in diameter, some internodes as much as 16 cm. long; leaves broadly 

 lanceolate, smooth beneath, scabrous and often with scattered white hairs above, 

 to 12 cm. long and 4 cm. wide; throat of leaf sheath with or without pubescence; 

 spathe stalk to 7 cm. long; spathes glabrous to very slightly pubescent with long 

 white hairs, 2-3 cm. long, 8-13 mm. high, open across top and down the side to 

 the spathe stalk, tapering to a blunt tip on abaxial end, the bottom forming a 

 straight line while the top is curved. 



On stream banks and in low thickets, a common garden weed, in e. Okla. 

 (McCurtain Co.) and e. Tex., May-Oct.; from S.D. to Tex., e. to the Atl. Ocean. 



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