56 



American Midland Naturalist Monograph No. 4 



Leaves reverse-egg-sha{>ed to wedge-shaped, green and smooth on both sides; 



western species found in Rocky Mountain parks 2. B. glandulosa. 



Leaves reverse-egg-shaped to round or kidney-shaped, green above, paler and 



glandular below; eastern species reported from Isle Royale 



3. D. pumila var. glandulifera. 



1. Water Birch, Moun- 

 tain Birch (Betula jont'.nalis 

 Sarg.), fig. H. — Tall spread- 

 ing shrub or slender graceful 

 tree with open crown; branches 

 slender, the twigs covered with 

 shiny resinous dots; bark red- 

 dish, not breaking into bands 

 or "curls" as in paper birch; 

 leaves thin, oval to roundish, 

 % to 2 inches long, pointed at 

 the tip, the margins toothed, 

 turning a beautiful clear yel- 

 low in the Fall; flowers and 

 fruits borne in small slender 

 catkins or cones about 1 to 1^/2 

 inches long, the scales falling 

 away when the seeds are ripe; 

 fruits tiny seed-like nutlets 

 with broad thin wings. Water 

 birch is also called red birch, 

 •black birch, or sweet birch. It 

 is commonly found along 

 streams or around springs. 



Fig. II. Water birch {Belula foniinalis) . 



Occurrence. — KINGS CANYON : between Junction Meadow and Charlotte Creek. GLA- 

 CIER, occasional: along creek near outlet of St. Mary Lake; Red Eagle Valley; shore 

 of St. Mary Lake near East Glacier Campgrounds. YELLOWSTONE, 6,500 to 7,500 

 feet: along Boiling River; near Firehole bridge. ROCKY MOUNTAIN, occasional. BRYCE 

 CANYON: near water fountain. Peek-a-boo trail. ZION, occasional 4,500 to 6,500 feet: 

 tiail from Lodge to Birch Creek; Weeping Rock; Emerald Pools; Grotto; west rim 

 ranger cabin. GRAND canyon. North Rim: Bright Angel Spring; around the springs in 

 South Big Spring Canyon ; near Kanabownitz Spring. Canyon, rare, north of the 

 Colorado River: Ribbon Falls, near Kaibab trail, 3,750 feet. 



2. Bog Birch (Betula glandulosa Mich.), fig. 12. — Spreading shrub, 1 to 

 8 feet high, branches dark reddish-brown, young twigs sticky, more or less 

 resinous; leaves small, roundish to reverse-egg-shaped with rounded tips and 

 toothed margins, smooth, 1/3 to 1 inch long; cones 1/3 to % inch long. This 

 species is also known as scrub birch. 



Occurrence. — glacier, occasional 5,000 to 7,500 feet: Garden Wall trail to Granite 

 Park; Swiftcurrent Lake near Many Glacier Hotel; north of Lake Janet; Gunsight 

 Pass; head of St. Mary Lake. YELLOWSTONE, occasional: south of Old Faithful; near 

 Firehole Bridge; along Boiling River near north entrance; near Rustic Falls, between 



