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- loothed ; 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. S. lucida. 



Flowers red. 



Flowers in flat cor^'mbs. 5. densiflora. 



Flowers in elongate panicles. 



Leaves tomentose beneath. S. 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 S. corymhosa 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 



