174 Flora of the Palouse Region 



ovate or lanceolate, acute, 8-20 mm. long: flowers blue, in a rather loose 

 spike; bracts like the leaves but broader: calyx-tube very narrow, becoming 

 3-4 cm. long and appearing like a pedicel; calyx-lobes narrow, unequal: 

 lower lip of the corolla sharply 3-lobed, 8-10 mm. long and broad, blue with 

 a large white and yellow center; divisions of the upper lip lanceolate. Com- 

 mon on the margins of ponds. 



Family 77. DIPSACEAE. 



Herbs: leaves opposite or wborled, without stipules: flowers in 

 dense heads, surrounded by an involucre as in the Compositae: 

 calyx-tube adherent to the ovary: corolla epigynous, 2-5-lobed: 

 stamens 2-4, distinct, on the corolla-tube and alternate with its 

 lobes: ovary inferior, 1 -celled; ovule 1: fruit an akene with persist- 

 ent calyx-lobes; endosperm fleshy. 



292. DIPSACUS. 



Rough-hairy or prickly tall biennial or perennial herbs: leaves 

 large, opposite, the bases sometimes united into a cup: flowers in 

 dense terminal peduncled oblong heads: bracts of the involucre 

 and scales of the receptacle rigid or spiny-pointed: calyx 4-toothed 

 or lobed: corolla oblique, 2 -lipped, 3-lobed: stamens 4: stigma ob- 

 lique or lateral: akene free from or adherent to the involucel. 



D. sylvestris Huds. Biennial, 1-2 m. high, the stems and midribs armed 

 with stout prickles: lower leaves lanceolate, obtuse, crenate, rarely cleft at 

 base, 15-30 cm. long; upper leaves sessile, often cuneate, acuminate, entire: 

 heads ovoid, becoming cylindric, 5-10 cm. long; involucre of linear cuspidate 

 prickly bracts, some of which are longer than the head: bracts of the recep- 

 tacle ovate, armed with long straight awns: flowers lilac. Sparingly intro- 

 duced on Union Flat. 



Family 78. COMPOSITAE. 



Annual biennial or perennial herbs or undershrubs (in ours): 

 leaves without stipules: flowers in a close head on a common re- 

 ceptacle, surrounded by one or more rows of bracts (the involucre); 

 heads i-many, discoid when all the flowers bear tubular corollas, 

 ligulate when the corollas are all strap-shaped, radiate when the 

 outer corollas are strap-shaped and the inner tubular, in which 

 case the outer are ray-flowers and the inner disk-flowers: receptacle 

 often covered with bracts or scales (chaff) each subtending a flow- 

 er: calyx gamosepalous, its tube wholly adherent to the ovary, its 

 limb (pappus) none or cup-shaped or developed into teeth, scales, 

 awns or capillary bristles: corollas alike in all the flowers of the 

 head or dissimilar, either tubular or strap-shaped (ligulate), gamo- 

 petalous, epigynous: stamens 5, epipetalous, their anthers united 

 into a tube (syngenesious): style 2-cleft at the apex or in sterile 



