April I, 1916 365 



Plkuropogon R. Br. Side beard. 



Pleuropogon ri'.fractum (Gia\) Vascy. i. Tuflcd side* 

 beard. Infrequent on moist banks, Halcli creek and Linntou 

 road. June to Aiio^ust. 



POA L. Meadow s:rass; blue grass. 



POA ANNUA L. I. Annual blue grass. Coniuion in fields 

 and waste places around Portland. Our earliest flowering grass. 

 Naturalized from Europe. Thorgli introduced, this species is 

 common on bottom lands along the lower Columbia river, and 

 will withstand two to three months submergence, say May i to 

 August I, without ajiparent injuiy. It and other boltom land 

 grasses usually grow at a little higher elevation than the bottom 

 land sedges, Carex aperta etc. April to October. 



Po.A NERVOSA (Hook.) Vase}'. 4. vSmoolh spear grass. Tall 

 perennial, infiequent in open places and rock)- slopes, Elk Rock, 

 etc. May to Jul)-. 



POA HowELi.il Vasey & Scribn. 4. Pale green spear grass. 

 Densely tufted perennial, on rocky slopes, Elk Rock and in open 

 woods near Oswego. May to July. 



PoA PRATENSIS L. 4. Blue grass. Variable perennial and 

 valuable forage grass, common in fields, meadows and waste 

 places evcrNwhere. May to August. 



POA COMPRESSA L. 4. Canada blue grass. Common in old 

 pastures, fields and waste places around Portland. Naturalized 

 from Europe. May to September. 



POA TRIFLORA Gilib. 4. {P. flovji.) Fowl meadow grass. 

 Common on moist slopes and river bottoms, Columbia slough. 

 A desirable forage grass, and, as well as the annual blue grass, 

 will withstand two or three months submergence on bottom 

 lands without apparent injury. June to August. 



POA GRACILUMA Vasey. 4. Slender spear grass. Densely 

 tufted perennial, infrequent on rocky cliffs near Oswego. June 

 to August. 



X POA MULTNOMAE Piper. 4. IMultuomah blue grass. 

 The type of this grass was collected by C. V. Piper in 1904 at 

 Multnomah Falls, which is somewhat beyond cur range, but the 

 species undoubtedly extends into our limits. June to August. 



