Sporobolus 



Agrostideae 



135 



76-230. SPOROBOLUS B. Br. Dropseed 



Lemma appressed-pubescent on the sides, at least near the base. 



Plant annual, more or less decumbent at the base; terminal panicles included (very 



rarely one free), lateral panicles common; spikelets 3.5-6 mm long 



1. S. vaginiflorus. 



Plant perennial, erect, not decumbent at the base; terminal panicles free (rarely one 

 partly included), lateral panicles absent (rarely one or more present); spike- 

 lets about 5-6 mm long 2. S. clandestinus. 



Lemma glabrous on the sides, the keel usually somewhat scabrous. 

 Spikelets of the terminal panicles 2-3 mm long. 



Plant annual; sheaths not bearded at the throat (sometimes a few long hairs on 

 the inside); terminal panicle less than 7 cm long, usually included, contracted 



and spikelike ; grain about 1-1.5 mm long 3. S. neglectus. 



Plant perennial; sheaths conspicuously bearded at the throat; terminal panicle 

 more than 7 cm long, usually almost free and widely spreading at maturity 



(sometimes included and spikelike) ; grain about 1 mm long 



A. S. cryptandrus. 



Spikelets of the terminal panicles 3.5-5 mm long. 



Glumes acuminate or aristate, the second one about 1-2 mm longer than the first; 

 panicles free at maturity and widely spreading; grain orbicular, smooth. 



5.5. heterolepis. 



Glumes obtuse, the second one about 1 mm longer than the first; panicles usually 

 included, contracted; grain flattened, reticulate 6. S. asper. 



1. Sporobolus vaginiflorus (Torr.) Wood. Map 229. Infrequent to com- 

 mon in all parts of the state. It prefers poor, dry soils and is rarely absent 

 from the borders of limestone highways. It seems to be spreading for I 

 have seen it spread over a fallow field and over vacant lots in a few years. 

 It can now be found almost everywhere along roads made of crushed rock, 

 in waste places, on washed slopes, and in poor soil in pastures. 



Maine, Ont. to Minn., southw. to Ga., Tex., and Ariz. 



2. Sporobolus clandestinus (Spreng.) Hitchc. (Including Sporobolus 

 canovirens Nash.) Map 230. Infrequent in very sandy soil in prairie 

 habitats in the counties shown on the map. The range will doubtless be 

 extended to include the counties about Lake Michigan. 



Conn, to 111. and Kans., southw. to Fla. and Tex. 



