146 



GRAMINEAE (GliASS FAMILY) 



137. B. oligostachya. 



Spikelet with glumes 



detached x 3. 



1. CHONDR6SIUM (Desv.) Gray. Spikes 1-4, usually curved, of 25 01 

 more densely crowded pectinate spikelets. 



1. B. oligostachya (Nutt.) Torr. Culms slender, erect, from a short root- 

 stock, leafy at the base, 1.5-5 dm. high ; sheaths and blades glabrous, the latter 

 about 2 mm. wide, flat or becoming convolute ; spikes 1-3, 

 2-5 cm. long; spikelets 5-6 mm. long; glumes narrow, the 

 first about as long as the second, which is sparsely papillose- 

 pilose on the keel; fertile lemma pilose, 3-cleft, the divisions 

 awned ; sterile lemma consisting of 2 truncate lobes and 3 

 divergent equal awns with a tuft of long hairs at base, second 

 rudiment obtuse, awnless. Prairies, Wis. and N. Dak. to 

 Tex. ; casual eastw. (Mex.) July-Sept. FIG. 137. 



2. B. hirsuta Lag. Culms tufted, erect, 2-5 dm. high, 

 leafy at the base ; sheaths smooth ; blades about 3 mm. wide, 

 flat, sparsely papillose- hairy, especially on 

 the margins; spikes 1-4, 1.5-5 cm. long; 

 the rhachis of the spike produced into a 

 prominent point beyond the uppermost spikelets; spikelets 

 about 5 mm. long ; first glume setaceous, the second equaling 

 the floret, conspicuously tuberculate-hirsute on the back; fer- 

 tile lemma pubescent, 3-cleft, the divisions awn-pointed ; 

 sterile floret of 2 obtuse lobes and 3 equal awns margined 188. B. hirsnta. 

 below, no tuft of hairs at the base. Sandy plains, Wis. to Spikelet with glumes 

 Mo. , and southwestw. to Mex. July-Sept. FIG. 138. detached x 3. 



2. ATHEROP6GON (Muhl.) Gray. Spikes 15 or more, of 12 or fewer ascend- 

 ing spikelets. 



3. B. curtip6ndula (Michx.) Torr. Culms erect from short running root- 

 stocks, 3-10 dm. high ; sheaths pubescent toward the summit ; blades 1-3 dm. 

 long, 3-5 mm. wide, flat or involute and setaceous toward 

 the end, scabrous above, sometimes pubescent beneath ; spikes 

 numerous, 8-16 mm. long, spreading or reflexed. in a long 

 mostly 1-sided raceme, the rhachis bifid at the extended apex ; 

 spikelets 7-10 mm. long ; first glume less than | the length 

 of the second which is very scabrous on the thickened keel, 

 exceeding the floret ; lemma scabrous, ending in 3 short 

 139. B. curtipendula. slender awns ; teeth of palea aristate ; sterile lemma icith 

 Part of inflorescence 2 acute lobes and 3 straight aicns, the lateral ones much 

 x%. shorter than the middle awn. (B. racemosa Lag.) Dry 



hills and plains, Ct. to Minn., s. to Tex. and Mex. July- 

 Sept. The sterile lemma variable, rarely reduced to a single awn. FIG. 139. 



55. CTENIUM Panzer. TOOTHACHB GRASS 



Spikelets with 1 perfect flower and 2-5 sterile lemmas, 

 crowded and sessile, pectinate in 1-sided spikes ; glumes very 

 unequal, first minute, second nearly as long as the spikelet, 

 bearing a stout horizontally divergent dorsal awn from about 

 the middle ; first and second lemmas empty or sometimes 

 with a hyaline palea, awned below the apex, awn erect or 

 ascending ; third lemma similar, containing a perfect flower ; 

 fourth awnless, staminate or empty ; a fifth rudimentary 

 lemma often present. Rather tall perennials with solitary 

 terminal more or less curved spikes. (Name from Kreviov, 

 a small comb, from the pectinate appearance of the spike.) 

 CAMPULOSCS Desv. 



1. C. aromaticum (Walt.) Hitchc. Culms 1-1.5 m. high, 

 erect, from scaly rootstocks, old sheaths persistent at the 

 base; blades long, flat or involute, stiff; spike 0.5-1.5 dm. 



140. C. aromaticum. 

 Inflorescence x *. 

 Spikelet x _'. 

 Sauie with glumes 

 detached x 2. 



