GENERA OF GRASSES OF THE UNITED STATES. 



217 



Syntherisma is included in Panicum by some botanists and in Pas- 

 palum by others. It differs from both in the cartilaginous rather 



than indurate fruit and in 

 the flat, white, hyaline 

 margins of the lemma. 



Our commonest species 

 is Syntherisma, sanguincdis 

 (L.) Dulac (Dig it aria 

 sanguinalis Scop.) ( fig. 

 130), usually called crab- 

 grass. This is a decumbent 

 or prostrate annual, usually 

 more or less purple, with 

 hispid sheaths, flat blades, 

 few to several slender digi- 

 tate or subdigitate spikes 

 or racemes, and a narrowly 

 winged rachis, the first 

 glume minute. Crab-grass 

 is a native of the Old 

 World, but is now widely 

 distributed in tropical 

 America, and is common in 

 cultivated soil throughout 

 the eastern and southern 

 part of the United States. 

 It is often a bad weed in 

 lawns. In the Southern 

 States, where crab-grass 

 produces an abundant 

 growth in the late summer 

 on the fields from which 

 crops have been gathered, 



FIG. 130. Crab-grass, Syntherisma sangwnaUs. ft is utilized for forage and 



"Plant- V 1 -ftirrt Trfck-wrc? f\f arvllr^lo-f n-n/1 -P^-n-f -il^ ^ 



Plant, X \ ; two views of spikelet and fertile 

 floret, X 10. 



is sometimes cut for hay. 



