130 



American Midland Naturalist Monograph No. 4 



egg-shaped, 3- to 5-lobecI, 1 to 3 inches long, or those of the sterile shoots 

 up to 4 inches long, usually softly fuzzy below with branched hairs; flowers 



white, about 1/2 itich across, borne in dense 

 rounded clusters U/z to 21/2 inches across, 

 the flower -stalks and calyces densely woolly; 

 pods 3 to 5, I/4 to % inch long, oblong- 

 egg-shaped with long tapering tips, smooth 

 when mature. 



Occurrence. — OLYMPIC : Crescent Lake. 

 MOUNT ra:nier. yosemite, rare: vicinity of Carl 

 Inn. SEQUOIA: Dorst Creek. 



5. Common Ninebark (Physocarpus 

 opulifolius (L.) Maxim.). — Similar to Pa- 

 cific ninebark but the shrubs in general 

 somewhat smaller and less straggly; leaf- 

 blades mostly 5-lobed, % to 2 inches long, 

 smooth or nearly so below; flowers about 

 Yg inch across, the flower-stalks and calyces 

 smooth or only sparingly hairy. 



Occurrence. — iSLE ROYALE, common : Mott 

 Island; Lake Richie trail; Raspberry Island. 



Fig. 65. Pacific ninebark Physo- 

 carpus capiiatns^ . 



RocKSPlREA (Holodiscus Maxim.) 



Several varieties of rockspirea are recognized in the western national parks. 

 Small scrubby forms found in the Southwest are quite in contrast to the 

 beautiful shrubs of the Pacific Northwest with their large sprays of creamy- 

 white flowers. The foliage is browsed to a certain extent by deer and elk. 



Field Guide to the Varieties 



Shrubs 3 to 6 feet high, or sometimes taller and almost tree-like; ieaf-blades thinnish, 

 % to 3 inches long; flower-clusters much-branched, 3 ot 12 inches long. 



Leaves slightly hairy; Pacific coast species ]. H. discolor. 



Leaves usually densely white-silky below, found in Rocky Mountain National 



Park I a. Var. dumosus. 



Shrubs I to 4 feel high; leaf-blades thickish, '/4 to % inch long; flower-clusters not 

 branched or with few branches, )/2 to 4 inches long. 



Leaf-blades 1/3 to % inch long, hairy, green above, paler below or white- 

 silky; occurs in Sierra Nevada parks lb. Var. microphallus. 



Leaf-blades '/4 to '/2 inch long, green on both sides, more or less hairy, gland- 

 dotted at least below; found mostly east of the Great Western Divide 

 I c. Var. glahrescens. 



1. Creambush Rockspirea, Oceanspray {Holodiscus discolor 

 (Pursh) Maxim.), fig. 66. — Spreading shrubs 3 to 15 feet high; bark gray- 

 ish; leaves egg-shaped to elliptic, the margins coarsely and irregularly toothed, 

 green above, paler and softly hairy below, 1 to 3 inches long; flower-clusters 

 large, broad, about 3 to 12 inches long, often 8 inches broad, tending to 

 droop; flowers tiny, creamy white, later becoming discolored and brownish 



