132 



American Midland Naturalist Monograph No. 4 



lb. Mountain Rockspi- 

 raea (Var. microphyllus 

 (Rydb.) Jepson), fig. 67.— 

 Low compact shrub 1 to 3 feet 

 high; leaf-blades i^ to % inch 

 long, wedge-shaped, green 

 above, paler and densely silky 

 below, often finely hairy above; 

 flower-clusters narrow, I/2 to 3 

 inches long, unbranched or with 

 few simple branches. (Syn. 

 Holodtscus discolor var. du- 

 mosus Jepson, in part.) 



Occurrence. — yosemite, coin- 



Fig. 68. Smooth rockspiraea {^Holodtscus dis- 

 color var. glabrescens). 



men, 4,000 to 10,000 feet: Mirror Lake; 

 Ledge trail; below Nevada Falls; Half 

 Dome; Tioga road; Lake Eleanor. 

 KINGS CANYON: East Lake; near Sphinx 

 Creek. SEQUOIA, occasional, 6.000 to 

 11,000 feet; Giant Forest; Alta Peak; 

 Lodgepole campground; Mount Whitney; 

 Pinto Lake. 



Ic. Smooth Rockspiraea (Var. 



glabrescens (Greenm.) Jepson), fig. 



68. — Much-branched shrubs 1/2 to 3 



feet high; leaves ^ to 1/2 inch long, 



thinly hairy and gland-dotted below 



and often so above, green on both sides; flower-clusters narrow, 2 to 4 inches 



long, unbranched or with few simple branches. (Syn. Spiraea dumosa Torr., 



not Nutt.; Sericotheca Schaffneri Rydb., as to Grand Canyon plants.) 



Occurrence. — CRATER LAKE, common, about 7,000 feet: Timber Crater; rim of 

 Crater Lake; Mount Scott; Wizard Island; Union Peak. LASSEN, occasional, 6,000 

 to 9,000 feet: Lassen Peak; Brokeoff Mountain; Manzanita Lake. BRYCE CANYON: 

 Biyce Point; Far View just below edge of cliff. ZION : west entrance checking station, 

 5,700 feet. GRAND CANYON, 6,500 to 9,100 feet. North Rim, common near edge of rim: 

 Grand Canyon Lodge; Bright Angel Point; Point Imperial; Neal Spring; Bright 

 Angel Spring. Canyon, below North Rim: Kaibab trail. 



Fig. 67. Mountain rockspiraea (Holo- 

 discus discolor var. microphvllus) . 



