SPERMATOPHYTA AMARANTHACEAE 



431 



Fig. 207. Russian Thistle (Salsola Kali, var. tenuifolia). 

 mechanical injuries to man and stock. (Charlotte M. King.) 



Causes 



stamens 1-5, mostly opposite the calyx-segments; ovary 1-celled; ovules solitary; 

 fruit an utricle; circumscissile, irregular or indehiscent; seed generally smooth; 

 endosperm usually copious and mealy. About 425 species in tropical countries 

 mostly. Several like Celosia cristata are cultivated for ornamental purposes and 

 several are weedy. Among the latter are the tumble-weed (Amaranthus graeci- 

 zans), pig- weed (A. retroflexus), and prostrate pig-weed (A. blitoides). The 

 leaves of several species are used as food. 





Amaranthus (Tourn.) L,. Pig-weed. Tumble-weed 



Annual, branching or erect herbs, smooth or pubescent leaves, simple ; small 

 flowers, monoecious, dioecious, or polygamous, green or purplish, generally with 

 3 bractlets; in spikes or axillary clusters; sepals 3-5, distinct; stamens 2-5; 

 styles 2-3; fruit oblong, utricle. About 50 species of wide distribution, mostly 

 of southern states. 



