150 Pipei — Nevj and Tiifcrrxting Amrriran Grasses. 



Oregon ; in Flett's No. 1383, from Skamania Co., Wash.; and in Piper's No. 

 3953 from Wawawai, Wash. This, of course, is an approach toward 

 Efi/nvis. In the plant described as Sitanion fiexuoKnm, not only are there 

 two spikelets at one or more joints of the rachis, but many of the empty 

 glumes, even where there is but a single spikelet, are long-awned and more 

 or less deeply Ijitid or trifid. The flowering glume has its apex more i)ro- 

 nouncedly l)ifid than in the typical form, and the teeth usually bear small 

 awns. Apart from these characters the spikelets are exactly those of .1. 

 spiraluin. The spike tends to be flexuous and nodding, but exactly this 

 same thing occurs in neighboring plants which otherwise are clearly 

 referable to A. Rjncatum. 



Elymus mollis Trin. 



Eiifinas capiiaius Scribn., U. S. Dept. Agr. Div. .\grost. Bull. II : .")5, 1898. 



The supposed species E. capUatu^ is merely a form of E. rnnllis Trin. niod- 

 itied by the attacks of nematode worms in the ovaries. This form is confined 

 almost entirely to sand dunes, in which localities from fifty to ninety percent, 

 of the plants have the heads thus aflected. The attacks of these microscopic 

 worms in E. mollis result in the heads becoming much shorter and broader, 

 so as to vary from subglobose to oblong, while the spikelets become some- 

 what proliferous, all the parts being abnormally elongated and less hairy. 

 It is not uncommon to find both normal and affected heads on the same 

 plant, the contrast in their forms Ijeing striking. El i/tiin.'< mollis is almndant 

 all along the .Alaskan coast, while the cay»//fl/t(.s form is plentiful on the. sand 

 dunes near Yakutat and on Cook Inlet near Homer and near Kenai. 



