ROSACEAE. 133 



186. AMELANCHIER. Service Berry. 



Shrubs or small trees, not thorny; leaves alternate, simple, 

 petioled, serrate or entire; flowers white, in racemes; calyx-tube 

 campanulate, 5-lobed, more or less adherent to the ovary; petals 

 5; stamens numerous, on the calyx-tube; styles 2-5, united below 

 or distinct; ovary 5-celled, each cell 2-ovuled; berry-like pome 

 10-celled, by the growth of a false partition in each cell of the 

 ovary; each cell 1-ovuled. 



Young leaves loosely tomentose beneath, toothed only above 



the middle. A.florida. 



Young leaves glabrous, mostly sharply serrate from the base. 



Young leaves bright green; petals nearly 2 cm. long. A. cusickii. 



Young leaves pallid; petals 1 cm. long. A. basalticola. 



Amelanchier florida Lindl. Shrub or small tree, 2-5 m. high; leaves 

 broadly oblong, rounded or subcordate at base, obtuse, tomentose when 

 young, especially beneath, glabrate, toothed above the middle or rarely entire, 

 2-4 cm. long; petioles pubescent, 1-2 cm. long; racemes 4-8 cm. long; calyx 

 pubescent, the triangular acute lobes not longer than the tube; petals ob- 

 lanceolate, obtuse, about 1 cm. long. Common along streams and on moist 

 hillsides. 



Amelanchier cusickii Fernald. Shrub, 3 -6 m. high, with numerous virgate 

 branches, the young bark chestnut-brown; leaves glabrous from the first, 

 oblong or orbicular, obtuse or acute, rounded or cordate at base, mostly sharply 

 serrate the whole length; petioles slender, glabrous; racemes short, dense; 

 calyx-lobes slightly hairy, acuminate, longer than the tube; petals oblong- 

 oblanceolate, obtuse, about 2 cm. long. Common on basalt ledges along the 

 rivers; blooming ten days earlier than A. florida. 



Amelanchier basalticola Piper. Small shrub, with pale bark, even on the 

 young branchlets; leaves appearing before the flowers, orbicular or oblong, 

 mostly truncate at base and apex, serrate above the middle or less commonly 

 from the base, glabrous and glaucous from the first, firm in texture, 1.5-2 cm. 

 long, on slender petioles, nearly as long; racemes very short, few-flowered; 

 calyx-lobes attenuate-acuminate, sparsely hairy, longer than the tube; petals 

 narrow, oblong-oblanceolate, obtuse, 10-12 mm. long; stamens 20, the filaments 

 united into a disk-like structure at the base; styles separate; mature fruit not 

 seen. Bluffs of Snake River. 



187. CRATAEGUS. Thorn. Hawthorn. 



Shrubs or small trees, mostly thorny; leaves alternate, petioled, 

 entire, serrate, lobed or pinnatifid; flowers white, rarely rose- 

 colored, in terminal corymbs; calyx-tube cup-shaped or cam- 

 panulate, adherent to the carpels, the Hmb 5-lobed; petals 5, 

 roundish, on the calyx-tube; stamens many, or only 5 or 10; 

 styles 1-5, separate; ovary inferior, or its summit free; ovules 

 one to each carpel; pome small, drupe-like, with 1-5 bony 

 carpels, each 1-seeded. 



Calyx pubescent; fruit red; spines 3-6 cm. long. C. Columbiana. 



Calyx nearly glabrous; fruit black; spines 1-3 cm. long. C. brevispina. 



