HEATH FAMILY 299 



3. Ledum columbianum Piper. Coastal Labrador Tea. Fig. 3673. 



Ledum columbianum Piper, Contr. U.S. Nat. Herb. U: 441. 1906. 



Erect shrub, seldom over 1 m. high, the branchlets more or less densely puberulent and some- 

 what glandular. Leaves Z-6 cm. long, elliptic-oblong, but appearing narrower on account of the 

 strongly revolute margins, green and rugose above, more or less whitish beneath with a fine 

 puberulence between the resinous dots ; petioles 5-10 mm. long ; pedicels densely puberulent and 

 glandular ; calyx-lobes ciliolate on the margins ; petals white, 5-6 mm. long, oblong, obtuse ; 

 stamens 5-7, rarely 10 ; filaments hairy below the middle ; capsule oblong, often acutish, 5-6 mm. 

 long, and nearly twice as long as broad. 



Sphagnum bogs and swamps in the coastal Canadian and Humid Transition Zones; along the coast and in 

 the lower altitudes of the Coast Ranges of western Washington and Oregon to the Santa Cruz Mountains, 

 California. Type locality: sphagnum bog at Ilwaco, Washington. May-July. 



3. RHODODENDRON L. Sp. PI. 392. 1753. 



Shrubs or small trees with glabrous, pubescent or glandular twigs. Leaves evergreen 

 or deciduous, usually alternate, entire, pubescent or glabrous. Flowers showy, in terminal 

 or lateral, umbel-like dusters. Calyx saucer-shaped, the lobes persistent, small or in one 

 species larger and foliaceous. Corolla turbinate-campanulate to funnelform, regularly or 

 irregularly 5-lobed. Stamens 5 or 10, slender, elongated and declined; anthers opening by 

 terminal pores. Ovary 5-celled ; style elongated, declined. Capsule 5-celled, septicidally 

 5-valved; seeds numerous, minute, wing-margined. [Name Greek, meaning rose-tree.] 



A genus of about 200 species widely distributed over the northern hemisphere, and most abundant in Asia. 

 Type species. Rhododendron ferrugineum L. 



Leaves deciduous, not thick and leathery. 



Inflorescence lateral; calyx-lobes foliaceous; corolla white, open-campanulate. 1. R. albiflorum. 



Inflorescence terminal; calyx-lobes small not foliaceous; corolla mostly pink, funnelform. 



2. R. occidentahs. 



Leaves evergreen, leathery; flowers rose-purple. 3. R. macrophyllum. 



L Rhododendron albiflorum Hook. White-flowered Rhododendron. Fig. 3674. 



Rhododendron albiflorum Hook. Fl. Bor. Amer. 2: 43. pL 133. 1834. 

 Asatea albiflora Kuntze, Rev. Gen. 387. 1891. 

 Cladothamnus campanulaius Greene, Erythea 3: 65. 189S. 

 Azalcastrum albiflorum Rydb. Mem. N.Y. Bot. Gard. 1 : 297. 1900. 



Erect shrub, 1-2 m. high, with slender branches and exfoliating bark. Leaves 2-7 cm. long, 

 thin, deciduous, oblong to broadly elliptic, acutish at apex, narrowed below to a short petiole, 

 loosely rusty-pubescent, entire or wavy-crenate ; flowers in 1-3-flowered lateral clusters, in the 

 axils of last year's leaves; pedicels slender, 10-15 mm. long; calyx-lobes oblong, 10 mm. long; 

 corolla creamy-white, open-campanulate, about 2 cm. broad, the lobes similar ; capsule 6-7 mm. 

 high. 



Mountain slopes near timber line, Hudsonian Zone; Cascade Mountains, British Columbia to Mount Hood, 

 Oregon, also in the Olympic Mountains, Washington, and the Blue Mountains, Oregon; extending eastward to 

 the Rocky Mountains. Type locality: "Alpine woods of the Rocky Mountains." July-Aug. 



2. Rhododendron occidentale A. Gray. Western Azalea. Fig. 3675. 



Asalea calif ornica Torr. & Gray, Journ. Acad. Phila. II. 3: 54. 1855. Not Rhododendron calif ornicnm Hook. 



Azalea occidentalis Torr. & Gray, Pacif. R. Rep. 4: 116. 1857. 



Rhododendron occidentale A. Gray, Bot. Calif. 1: 458. 1876. 



Rhododendron sonomense Greene, Pittonia 2: 171. 1891. 



Rhododendron occidentale var. palttdosum Jepson, Man. Fl. PI. Calif. 741. 1925. 



Loosely branching shrub, 1-4 m. high, with shredded bark and somewhat glutinous or some- 

 times short-pubescent twigs. Leaves deciduous, thin and light green, 3-9 cm. long, elliptic to 

 oblong-oblanceolate, obtuse or acute, gland-tipped, sparsely pubescent on both surfaces or some- 

 times glabrous, short-petioled ; inflorescence terminal, more or less glandular-pubescent; calyx- 

 lobes ovate to oblong, 4-5 mm. long, ciliate; corolla funnelform, 3.5-5 cm. long, deeply and 

 slightly irregularly lobed, the lobes oblong-lanceolate, white or more or less tinged with pink, 

 the upper lobes often with a yellow splotch ; stamens 5, well exserted ; ovary densely glandular- 

 pubescent. 



Stream banks and moist mountain meadows and flats, Transition Zone; Douglas County, Oregon, south 

 through the Coast Ranges, Siskiyou Mountains and Sierra Nevada to San Diego County, California. Type local- 

 ity: "Laguna de Santa Rosa," Sonoma County, California. April-Aug. 



3. Rhododendron macrophyllum D. Don. California Rhododendron. Fig. 3676. 



Rhododendron macrophyllum D. Don ex G. Don, Gen. Hist. PI. 3 : 843. 1834. 

 Rhododendron californicum Hook. Bot. Mag. 81: pi. 4S63. 1855. 



Shrub or small tree, 2-5 m. high, with glabrous twigs. Leaves evergreen, thick and coria- 

 ceous, dark green above, paler beneath, 6-20 cm. long, oblong to elliptic-oblanceolate, obtuse at 

 apex, glabrous, narrowed at base to short stout petioles ; calyx-lobes short, broader than long ; 



