124 



POACEAE 



15. TORRESIA Ruiz & Pav. Syst. Veg. Peruv. Chil. 251. 1798. 

 [Savastana Sclirank, 1789, not Savastania Scop. 1777; Hierochloe R. Br. 1810.] 

 Spikelets with one terminal perfect floret and 2 lateral staminate florets, disarticulating 

 above the glumes ; glumes equal, broad, thin and papery, smooth, acute ; sterile lemmas 2, 

 about as long as the glumes, mostly somewhat appressed-hispid, sometimes awned from 

 between two lobes ; fertile lemma somewhat indurate, about as long as the others, smooth 

 or nearly so, awnless ; palea 1-3-nerved, rounded on the back. Perennial low erect sweet- 

 smelling grasses with small panicles of bronze-colored spikelets. [Name in honor of the 

 Spanish gardener, de la Torre.] 



Species about 17 in the arctic and cool regions of the world. Type species, Torrcsia utriculata Ruiz & Pav. 

 Blades numerous in a basal cluster, usually 8-14 mm. wide, the uppermost leaf with a short blade; florets 



sparsely villous. 1. T. maciophylla. 



Blades scattered, usually less than 5 mm. wide, the uppermost leaf reduced to a sheath; florets densely 

 villous. 2. T. odorata. 



1. Torresia macrophylla (Thurb.) Hitchc. 

 California Vanilla Grass. Fig. 262. 



Hierochloe macrophvlla Thurb.; Boland. Trans. Calif. Agr. Soc. 



1864-65: 132. 1866. 

 Sa-^'astana macrophvlla Beal, Grasses N. Am. 2: 187. 1896. 

 Torrcsia macrophylla Hitchc. Am. Journ. Bot. 2: 300. 1915. 



Culms few, erect, 60-90 cm. tall ; sheaths scabrous ; 

 blades crowded toward base, flat, rather stiffly up- 

 right, scabrous above, glaucous beneath, acuminate- 

 pointed. 6-14 mm. wide ; panicle somewhat open, 7-12 

 cm. long, the lower branches spreading or drooping, 

 2.5-5 cm. long ; glumes 4 mm. long. 



In woods in the redwood belt from Oregon southward to 

 Monterey; also at Bingen, Washington (Suksdorf). May-July. 

 Type locality: Marin County, California. 



2. Torresia odorata (L.) Hitchc. 

 \'anilla Grass. Fig. 263. 



Holciis odoratus L. Sp. PI. 1048. 1753. 



Hierochloa borealis Roem. & Schult. Syst. Veg. 2: 513. 1817. 



Hierochloa odorata Wahl. Fl. Ups. 32. 1820. 



Savastana odorata Scribn. Mem. Torrey Club 5: 34. 1894. 



Torresia odorata Hitchc. Am. Journ. Bot. 2: 301. 1915. 



Culms 30-60 cm. tall ; panicle pyramidal, 4-8 cm. long, 

 usually rather compact; spikelets 5 mm. long; staminate 

 lemmas hispid-ciliate on the margins, awnless. 



Moist meadows. Cascade Mountains, Washington and Oregon, 

 eastward across the continent; also in Eurasia. Apr.-July. Type 

 locality, European. 



16. ARISTIDA L. Sp. PI. 82. 1753. 

 Spikelets 1-flowered, the rachilla disarticulating obliquely above the glumes; glumes 

 narrow, acute, acuminate or somewhat awned; lemma indurate, narrow, terete, convolute, 

 tipped below by the pointed, usually minutely bearded callus, terminating above in a usually 

 trifid awn. Annual or perennial, mostly low grasses, with narrow frequently convolut'j 

 lilades and narrow or sometimes open panicles. [Latin, arista, an awn.] 



Species about 150 in the warmer regions of the world. Type species, Aristida adscensionis L. 



Neck of fruit jointed at base. 1. A. calif ornica. 



Neck of fruit not jointed at base. 



Lateral awns wanting or reduced to mere points. 2. A. schicdeana. 



Lateral awns evident. 



Panicle diffuse, open, the main branches usually horizontally spreading or divaricate; glumes about 



equal; plants perennial. . . i. A. divaricata. 



Panicle narrow, somewhat open, the branches not divaricate. 

 Plants annual. 



Glumes 20-30 mm. long, nearly equal; awns 4-7 cm. long. 4. A. oligantha. 



Glumes not over 10 mm. long, the lower about half as long as the upper; awns about 1 cm. long. 



5. A. adscensionis. 



6. A. parishii. 



Plants perennial. 



Glumes about equal. 



Glumes unequal, the first half to two-thirds as long as the second. 



Neck of fruit slender, straight or slightly twisted, about as long as the body; panicle 



narrow, strict. 7. A. reverchoni. 



Neck of fruit short or not differentiated from the body. 



Pedicels slender, more or less recurved. 8. A. purpurea. 



Pedicels stiffly erect. 



Panicle elongate, many-flowered; collar of leaf bearing a ciliate line. 



9. A. wrightii. 

 Panicle short, few-flowered: no ciliate line on collar of leaf. lO. A. fendlcnana. 



II 



