202 ROSACEAE. 



269. HOLODISCUS. 



Thornless shrubs; leaves alternate, simply pinnately toothed 

 or lobed, without stipules; flowers numerous, white, in terminal 

 panicles; calyx deeply 5-lobed; petals 5, as long as the calyx 

 lobes, rounded; stamens 20, on a perigynous entire ring-like 

 adherent disk, scarcely exserted; pistils 5, each with 2 ovules, be- 

 coming 1 -seeded hairy carpels almost indehiscent. 



Holodiscus discolor (Pursh) Maxim. Ocean Spray. Iron-wood. 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, much branched, 10-20 cm. long; 

 flowers small, white, becoming yellowish; calyx densely short-pubescent, the 

 lobes acute, spreading. 



In open woods, abundant. 



270. SPIRAEA. 



Shrubs; leaves alternate, simple, without stipules; flowers white 

 or pink, perfect, in racemes, cymes, corymbs, or panicles; calyx 

 4- or 5-lobed; petals 4 or 5, exceeding the calyx and inserted on 

 the calyx-tube ; stamens numerous, distinct, on a disk which is 

 free at the edge and crenate or glandular-toothed ; filaments much 

 exserted; pistils commonly 5, superior, alternate with the calyx- 

 lobes; ovules 5-11; follicles usually 5, not inflated, 1-valved; 

 seeds few to several. 



Low depressed shrubs with entire leaves. 5. hendersoni. 



Taller shrubs with serrate or incised leaves. 



Flowers white. -5. lucida. 



Flowers red. 



Flowers in flat corymbs. 5. densiflora. 



Flowers in elongate panicles. 



Leaves tomentose beneath. 5. douglasii. 



Leaves glabrous beneath. S. menziesii. 



Spiraea hendersoni (Canby) Piper. Densely matted low shrub with the 

 leaves in rosettes; leaves oblanceolate, glabrous or nearly so, thick, pale green; 

 flowering stem 5-10 cm. high; raceme dense, 2-3 cm. long. 



In rock crevices on high peaks in the Olympic Mountains. 



Spiraea lucida Dougl. 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 glabrous on both sides; petioles 

 short; inflorescence a flat-topped dense corymb, 5-12 cm. across; flowers small, 

 white; carpels 5, glabrous. 



At low altitudes in the mountains. Very feebly distinguishable from the 

 eastern 5. corymbosa Raf. 



Spiraea densiflora Nutt. Stems erect, 30-100 cm. high; leaves ovate or 

 elliptic, serrate near the apex, usually obtuse; flowers in dense corymbs; petals 

 rose-colored. 



In the mountains at 1500-2000 m. elevation, near the limit of trees. 



Spiraea douglasii Hook. Stems erect, 1-2 m. high; leaves oblong, serrate 



