94 Flora of the Palousc Regio?i 



151. PHYSOCARPUS. 



Branching shrubs: leaves petioled, simple, palmately-lobed: 

 flowers in umbel-like corymbs: calyx 5-lobed: petals 5, round, on 

 the calyx-tube: stamens many, distinct, on the calyx-tube: pistils 

 1-5, more or less united: follicles 1-5, 2-valved; seeds 

 2-4; endosperm copious. 



P. pauciflorus Piper, n. comb. (Spiraea pauciflora Nutt ) Erect shrubs, 

 about 1 in. high, the branches spreading or recurved, the bark shreddy, 

 leaves broadly ovate or orbicular, bluntly 3-5-lobed, somewhat doubly den- 

 tate, nearly glabrous above, pubescent beneath with stellate hairs, 2-8 cm. 

 long; petioles 1-2 cm. long: inflorescence a corymb, 3-5 cm. broad, woolly- 

 pubescent throughout; pedicels slender: calyx broadly campanulate, the 

 blunt lobes as long as the tube: petals white, obovate, longer than the 

 calyx-lobes: carpels 2-3, pubescent, flattened, somewhat united at the base, 

 as long as the calyx, tardily dehiscent. Mostly in pine woods, common. 



152. SPIRAEA. 



Shrubs or perennial herbs: leaves alternate, simple or pinnate, 

 with or without stipules: flowers white or pink, perfect, in racemes, 

 cymes, corymbs or panicles: calyx 4-5-lobed: petals 4-5, exceed- 

 ing the calyx and inserted on the calyx-tube: stamens numerous, 

 distinct, on the calyx-tube; filaments much exserted: pistils com- 

 monly 5, rarely 1-8, superior, alternate with the calyx-lobes; 

 ovules 5-1 1 : disk free at the edge, crenate or glandular-toothed: 

 follicles usually 5, not inflated, i-valved; seeds few-several. 



Flowers panicled, red. S. menziesii. 



Flowers corymbose. S. corymbosa. 



S. menziesii Hook. Erect shrub, 1-1.5 m. high, not much branched, 

 minutely pubescent on the young twigs and under side of the leaves: leaves 

 oblong, acute or obtuse, rounded or cuneate at base, green on both sides, 

 coarsely serrate above the middle, rarely entire, 3-6 cm. long; petioles short: 

 panicles dense, pyramidal or oblong, 5-20 cm. long: flowers rose-colored: 

 calyx-lobes becoming reflexed: carpels 5, glabrous. Near Palouse City. 



S. corymbosa Raf. (S. lucida Greene.) Low shrub, 30-60 cm. high, 

 branched below: leaves elliptic or ovate, rounded at base, 2-6 cm. long, 

 coarsely and unevenly serrate or incised above the middle, green and glab- 

 rous on both sides; petioles short: inflorescence a flat-topped dense corymb, 

 5-12 cm. across: flowers small, white: carpels 5, glabrous. Common in open 

 woods or copses. 



153. HOLODISCUS. 



Much like the preceding genus, but petals as long as the calyx: 

 filaments scarcely exserted: ovules 2: disk wholly adherent, entire. 



H. discolor Maxim. Large shrub, 2-5 m. high: young twigs pubescent: 

 leaves triangular-ovate, mostly obtuse, truncate or cuneate at base, woolly- 

 pubescent beneath, glabrous above, 2-5 cm. long: panicle broadly pyramidal, 



