134 ROSACEAE. 



Crataegus coliunbiana Howell. A much-branched shrub, 2-4 m. high; 

 bark of older stems light gray; that of the younger twigs light brown, the 

 lenticels consplfcuous; the branches of the season and the inflorescence strigose- 

 villous; thorns 2-5 cm. long, dark-brown, shining, straight or nearly so, some- 

 what reflexed; petioles 1-2 cm. long, bearing several glands; leaf-blades broadly 

 oval in outline, sparingly strigose on both sides, dark and glossy above, paler 

 and dull beneath, incised and doubly serrate at or above the middle but merely 

 serrate on the cuneate base; teeth sharp and gland-tipped; apex short, acu- 

 minate; corymbs 4-1 2-flowered ; calyx villous; sepals 3-5 mm. long, promi- 

 nently glandular-dentate; anthers white; fruit spherical or nearly so, about 

 12 mm, in diameter, coral-red, glabrous; nutlets ridged on the back, without 

 cavities on the ventral faces. Springy gravelly places, infrequent. 



Crataegus columbiana piperi (Britt.) Eggleston. More pubescent; 

 calyx and pedicels somewhat villous; fruit pubescent. More common than 

 the species and intergrading with it. 



Crataegus brevispina (Dougl.) Heller. Shrubs, 2-6 m. high; spines stout, 

 2-3 cm. long; leaves obovate, broadly cuneate at base, coarsely doubly dentate 

 above the middle, acute or obtuse, sparsely pubescent on both sides when young, 

 paler beneath, -2-5 cm. long; petioles short, glandless; corymbs usually many- 

 flowered; flowers about 12 mm. broad; calyx-tube glabrous, the lanceolate 

 lobes pubescent; anthers pink; fruit black, smooth; nutlets with cavities on the 

 ventral faces. Common along streams. 



188. PYRUS. 



Trees or shrubs, not thorny (in ours); leaves simple or com- 

 pound; flowers in corymbed cymes; calyx urn-shaped, 5-cIeft; 

 petals roundish or obovate; stamens numerous; styles 2-5; 

 pome fleshy or berry-like, the 2-5 carpels or cells of a papery or 

 cartilaginous texture, 2-seeded. 



Pyrus sitchensis (Roem.) Piper. Mountain Ash. Shrub, 2-5 m. high, with 

 smooth bark; young branches pubescent; leaves pinnate, 12-20 cm. long; 

 leaflets 4^6 pairs, mostly oblong, acute or acuminate, simply or doubly serrate, 

 glabrous or nearly so, shiny above, 2-6 cm. long, 1-2 cm. broad; cymes dense, 

 compound, 8-12 cm. broad; flowers white, 8 mm. broad; calyx and pedicels 

 loosely woolly-pubescent; fruit bright-red, about 6 mm. in diameter. In 

 mountain woods. 



189. OPULASTER. Ninebark. 



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. 



Carpels pubescent, not exceeding the calyx. 0. pauciflorus. 



Carpels glabrous, much exceeding the calyx. 0. opuUfoUus. 



Opulaster pauciflorus (T. & G.) Heller. (0. malvaceus Greene.) Erect 

 shrubs, about 1 m. high, the branches spreading or recurved, the bark shreddy; 

 leaves 2-8 cm. long, broadly ovate or orbicular, bluntly 3-S-lobed, somewhat 

 doubly dentate, nearly glabrous above, pubescent beneath with stellate hairs; 

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



