15 



25. Spikelets 4 mm. loug or less 26 



26. Sjiikelets 3 to 4 mm. loug, panicle usually loosely ilowered 27 



26. Spikelets 2 to 2.5 mm. loug, panicle rather densely flowered. 25. C. macouniana. 



27. Panicle branches conspicuously flexuous, awn attached near apex of glume and 



considerably exceeding it 23, C. blanda. 



27. Panicle branches not conspicuously flexuous, awn attached usually near middle, 



equaling or slightly exceediug it 24. C. canaden.sis. 



28. Leaf-blades flat or nearly so, panicle not spiciform 29 



28. Leaf-blades strongly iuvolute 33 



29. Empty glumes not setaceous-pointed, prolongation of rachilla bearded its whole 



length, caryopsis glabrous 30 



29. Empty glumes setaceous-pointed, prolongation of rachilla bearded only near 



summit, caryopsis pubescent especially at summit 30. C. cinnoides. 



30. Callus hairs copious, f as long to longer than glume 31 



30. Empty glumes nari'ow lanceolate, callus hairs sparse, i as long as glume or less 



32 



31. Not ctespitose, longer callus hairs not equaling glume 26. C. scribneri. 



31. Strongly ctespitose, longer callus hairs considerably exceediug glume 



27. C. alaskana. 



32. Tall (9 to 12 dm.), sheaths bearded at summit 28. C. cusickii. 



32, Usually low (not exceediug 8 dm.), sheaths not bearded 29. C. scopiilorum. 



33. Culms and usually almost filiform leaf-blades soft, not rigid, plant not ca-spitose 



or not strongly so 34 



33. Culms and (usually) wider leaf-blades hard, more or less rigid 36 



34. Panicle dense, narrow, spike-like 35 



34. Panicle loosely flowered, open, flexuous 31. C. laxiflora. 



35. Spikelets 2.5 to 4 mm. long, empty glumes thin, acute sharp-acuminate 



32. C. ueglecta. 



35. Spikelets 2 mm. loug, empty glumes thickish, barely acute.. 33. C. micrantha. 



36. Panicle elongated, not spike-like, rather loosely flowered, plant tall, not ca^spi- 



tose or but slightly so 37 



36. Panicle usually short, dense, spike-like, i^laut usually low, strongly ctespitose. 38 



37. Ligule 4 to 6 mm. loug, hairs of callus about equaling glume. 34. C. inexpansa. 



37. Ligule 2 to 3 mm. long, hairs of callus I to I as long as glume. 35. C. califoruica. 



38. Not exceeding 5 dm. in height, panicle slender, much interrupted toward l>ase, 



awn not nearly equaling glume 36. C. labradorica. 



38. Panicle thick, not conspicuously interrupted, awn nearly eciualing to slightly 



exceeding the flowering glume 39 



39. Taller (4 to 12 dm.), panicle larger (5 to 20 cm. long), empty glumes merely lirm- 



membranous, oblong-lanceolate to ovate-lanceolate, short-acuminate 



37. C. hyperborea. 



39. Low (not exceeding 5 dm. ), panicle small (4 to 6 em. long), empty glumes almost 

 coriaceous, broad ovate, acute 38. C. crassiglumis. 



A. Aivn stronf/ly geniculate, conspicuously exsertcd, callus hairs nsualli/ much shorter than 



the flower in fi (jluiue. 

 a. Awyi greatly exceeding the empty glumes. 

 * Panicle loosely flowered, branches spreading. 

 t Xot c(es])itose, panicle dark-hrown purple. 

 1. Calamagrostis bolanderi Thnrb. ; S. Wats. Bot. Calif. 2: 2sO (1880). C. raria 

 Boland. in Thurb. 1. c, not D. C. Deyeuxia bolanderi Scribn., Bull. Torr. Club. 

 10: 8 (1883). 



Northern California. 



Type specimen collected in swamps, Mendocino County, by H. N, Bolander (Xo. 

 6471 in part). 



