51 



10. D. Howcllii, Vasey. Oregon and Washington. 



11. D. Langsdorfii, Kth. New England to Rocky Mountains. 



12. D.? Lapponica, Kth. Canada.to Rocky Mountains. 



13. D. Macouniana, Vasey. British America. 



14. DJ neglecta, Kth. (0. stricta, Nv.tt.) Rocky Mountain region. 



15. D. Nuttalliana, Vasey. (C. Nutta-lliana, Steud.) New Eng- 



land to North. Carolina. 



16. D. Pickeringii, Vasey. (C. Piekeringii, Gr.) New England 



to Caiiada. 



17. D. Porteri, Vasey. (C. Porteri, Gr.) Pennsylvania. 



18. D. purpurascens, Kth. Alaska. 



19. D. ruhescens, Vasey. (0. rubescens, Buckl.) California to 



Oregon. 



20. D. strigosa, Kth. Alaska. 



21. D. sylvatica, Kth. New England to Rocky Mountains. 



22. D. Suksdorfii, Scrib. "Washington Territory and Oregon. 



Ammophila, Host. (Calamagrostis.) 



■ Spikelets-one-nowered, in a contracted spike-like or an open, dif- 

 fuse panicle, with or without a bristle-like rudiment opposite the 

 palet ; outer glumes large, nearly equal, rigid, thick, lanceolate, 

 acute, keeled, five-nerved ; flowering glume similar in texture, about 

 equal in length, sometimes mucronate at the apex ; palet as long as 

 its glume, of similar texture, twb-kecled, snlcate between the keels ; 

 hairs at the base of the flower usually scanty and short. 

 1. A. arundinacea, Host. Sea coast. (Psamma, Beauv.) Beach 

 grass. Sand grass. 



This is the Calamagrostis arenaria of the older books. The en- 

 tire plant is of & whitish or pale-green color. It grows on sandy 

 beaches of the Atlantic at least as far south as North Carolina, and 

 on the shores of the Great Lakes, but has not so far been recorded 

 from the Pacific coast. It also grows on the sea-coast of the British 

 Isles and of Europe. It forms tufts of greater or less extent, " its 

 long creeping roots extending sometimes to the extent of 40 feet, 

 and bearing tubers the size of a pea, interlaced with death-like 

 tenacity of grasp, and form a net-work beneath the sand which re- 

 sists the most vehement assaults of the ocean waves." The culms 

 are from 2 to 3 feet high, rigid and solid ; the leaves long, involute, 

 smooth, rigid, and slender-pointed ; the panicle dense, 6 to 10 inches 



