226 Key to the System of 



1059. Involucral bracts beset with hairlets inside ... lf)60 

 Involucral bracts glabrous on both sides ... ... 1061 



1060. Leaves flaccid, rather elongated, flat, their lateral 



venules conspicuous. 



Finally tall, leaves rather large, spreading, flat, generally 

 from oval- to elliptical-lanceolar, almost membranous 

 and glabrous ; involucral bracts usually four, nearly as 

 long as the flowers, from orbicular to ovate and pointed ; 

 flowers comparatively large, in singly terminal headlets 

 numerous ; calyx whitish, beset with appressed hairlets 

 outside ; fruit dry. P. ligustrina. 



Leaves firm, rather abbreviated, incurved at the 

 margin, their lateral venules inconspicuous. 



A mostly slender shrub, never very tall ; leaves glabrous, 

 from broad- to narrow-lanceolar, pointed ; involucral 

 bracts four, concave, closely appressed, almost ovate, but 

 much pointed, inside beset with shining appressed hair- 

 lets ; flowers in singly terminal headlets ; calyx rather 

 large, whitish, invested with short silky-shining hairlets ; 

 fruit dry. P. stricta. 



1061. Calyx scantily beset with hairlets. 



A slender shrub, never very tall ; leaves from spatular- to 

 linear-elliptical, glabrous, somewhat incurved at the 

 margin ; involucral bracts four, mostly lanceolar-ovate; 

 flowers in singly terminal headlets ; calyx whitish ; fruit 

 dry. P. spatulata. 



Calyx densely beset with hairlets ... 1062 



1062. Leaves incurved at the margin. 



A slender shrub, never tall ; leaves firm, from lanceolar- to 

 linear-elliptical, three-nerved, glabrous, their margin and 

 also lateral venules somewhat prominent; involucral bracts 

 four, rather rigid, from elliptical to ovate, conspicuously 

 venulous ; flowers in singly terminal headlets ; calyx 

 whitish, beset with appressed hairlets ; fruit dry. 



P. collina. 

 Leaves recurved at the margin. 



A slender shrub, finally somewhat tall ; leaves from broad- 

 linear to narrow-elliptical or occasionally somewhat 

 lanceolar or spatular, glabrous ; involucral bracts four, 

 usually lanceolar-ovate, dissimilar to the leaves ; flowers 

 in singly terminal headlets ; calyx whitish, beset with 

 appressed hairlets ; fruit dry. P. linifolia. 



