158 GRAMINEAE 



Refs. POA GRACILLIMA Vasey, Contr. Nat. Herb. 1: 272. 1893. P. invaginata Scribn. & 

 Williams, U. S. Dcpt. Agr. Div. Agrost. Circ. 9: 6. 1899, type from "Summit Camp, Sierra 

 Nevada, July 10, 1870." 



22. P. unilateralis Scribn. Tufted perennial; culms 4 to 15 inches high; 

 sheaths smooth, tawny and papery; blades flat or folded, shorter than the 

 culms; panicle oblong, dense and spike-like, or somewhat interrupted below, 

 1 to 3 inches long; spikelets 3 to 4 lines long, perfect; glumes broad, acute, 

 smooth, indistinctly scabrous on keel near apex, the first 1-nerved or indis- 

 tinctly 3-nerved. the second 3-nerved ; lemmas 2 lines long, not webbed at base 

 or pilose, scabrous on base of marginal nerves and apex of keel, the inter- 

 mediate nerves faint ; palea ciliate on keels. 



Cliffs, bluffs and rocky meadows near the seashore, Humboldt Co. to Mon- 

 terey. 



Locs. Humboldt Bay, Chandler 1140; Mendocino, McMurphy 399; Pt. Arena, Davy fy 

 Blasdale 6024; Bodega Bay, Heller 5279; Pt. Eeyes, Davy 6765, 6804, 6881; San Francisco, 

 Abrams 1599; Montara Pt., Copeland 3306; Santa Cruz, Anderson; Monterey and vicinity, 

 Davy 7293, Heller 6702. 



Refs. POA UNILATERALIS Scribn.; Vasey, U. S. Dept. Agr. Div. Bot. Bull. 13 2 : pi. 85. 

 1893, type from San Francisco, Jones 15 in 1882 ; Davy in Jepson, Fl. W. Mid. Cal. 67. 1901. 

 Atropis procumbens Thurb. in Wats. Bot. Cal. 2: 309. 1880. This name is based on Poa 

 procumbens Curt, but the specimen in the Gray Herbarium (Bolander 6467, seashore at Fort 

 Bragg, Mendocino Co.) cited by Thurber, consists mostly of Poa unilateralis and this is the 

 species described. But mounted with this is a fragment of Sclerochloa procumbens Beauv. 

 It as not impossible that this fragment may have been detached from a European specimen by 

 Dr. Thurber, for comparison with the Bolander specimen and not afterwards removed. 

 Sclerochloa procumbens is not known to grow on the Pacific Coast. 



23. P. thurberiana Vasey. Tufted perennial; culms 2 to 3 feet high, 

 smooth; sheaths somewhat scabrous, the basal smooth and papery; ligule 

 1 to 2 lines long; blades narrow, involute, scabrous; panicle narrow, 8 to 10 

 inches long, loose, the branches long, ascending ; spikelets 2 lines long, 1 or 2- 

 flowered; glumes l 1 /^ lines long, 3-nerved; lemmas 1^ lines long, scaberu- 

 lous, not pilose or webbed. 



Little known. Aside from the type collection by Lemmon, in Sierra Valley, 

 this species was collected by Bolander (Los Angeles?) and what appears to be 

 the same species by Chase at Santa Barbara (no. 5604). 



Refs. POA THURBERIANA Vasey, U. S. Dept. Agr. Div. Bot. Bull. 13 2 : pi. 84. 1893. Panic- 

 ularia thurberiana Kuntze, Rev. Gen. PI. 2: 783. 1891. Atropis pauciflora Thurb. in Wats. 

 Bot. Cal. 2: 310. 1880 (type from Sierra Valley, Lemmon), not Poa pauciflora Roem. & Schult. 

 1817. 



24. P. hanseni Scribn. Tufted perennial; culms erect, slender, 6 to 8 inches 

 high or sometimes taller, smooth; sheaths smooth; ligule % to 1 line long; 

 blades capillary, involute, smooth, mostly basal ; panicle narrow, 1 to 2 inches 

 long ; spikelets 2 to 3 lines long ; glumes 1% to 2 lines long ; lemmas scaberu- 

 lous but not pilose or webbed. Differs from P. pringlei in being more delicate 

 and in having smaller spikelets. 



A little known species from isolated localities in California. Modoc Nat. For., 

 Hatton 63 ; Plumas Co., Heller 8751 ; Tuolumne Meadows, Hall & Babcock 3627 

 in part ; Loma Prieta, Davy 534. 



Ref. POA HANSENI Scribn. U. S. Dept. Agr. Div. Agrost. Bull. 11: 53. pi. 9. 1898, type 

 from Silver Lake, Amador Co., Hansen 605. 



25. P. idahoensis Beal. Tufted perennial; culms slender, 6 to 18 inches 

 high, smooth, slightly scabrous below the panicle; sheaths loose and papery, 

 smooth; blades capillary, soft, scabrous, the basal as much as 10 inches long; 

 panicle narrow, contracted but loose, 1 to 2 inches long; spikelets 21/2 to 3 lines 



