204 American Midland Naturalist Monograph No. 4 



CRATER LAKE, common, 5,000 to 6,500 feet: near park headquarters. GLACIER, abun- 

 dant, 3,100 to 6,500 feet: Belton, near park headquarters; abovs Lake Ellen Wilson; 

 trail to Trout Lake above Lake McDonald; Going-to-the-Sun Highway below the 

 hairpin turn; Cut Bank Valley; above St. Mary Lake; trail above Elizabeth Lake. 

 YELLOWSTONE: West Thumb. GRAND TETON: Jackson Lake; near mouth of Death 

 Canyon. 



The low fotm usually less than two feet high found in Rocky Mountain 

 parks has been described as Vaccmium globulare Rydb. It differs from V. 

 membranaceum in having smaller leaves, % to I1/4 inches long, usually pale 

 below, the berries smaller, globose, purple-black, usually with a bloom. Al- 

 though the extremes are quite distinct, in places where both forms occur it is 

 difficult to draw the line between them. 



Crowberry Family (Empetraceae) 



Black Crowberry, Wineberry {Empetrum nigrum L.). — Low creep- 

 ing evergreen shrub with prostrate stems 6 to 15 inches long and numerous 

 spreading branchlets; leaves crowded on the stems, linear, blunt-pointed, 

 grooved on the lower side; flowers small, mostly with 3 sepals and petals, 

 borne singly in the leaf-axils; berries small, black, containing 6 to 9 seeds 

 or nutlets. 



The generic name, Empetrum, comes from the Greek en, upon, and 

 petros, rock, alluding to the fact that it is often found growing on rocks, over 

 which it may form dense clinging carpets. The tiny black berries are eaten 

 by birds. 



Occurrence. — OLYMPIC: moraine at edge of Blue Glacier, 4,000 feet. MOUNT RAI- 

 NIER, cominon at about 7,500 feet. ISLE ROYALE, occasional on rocks: Scoville Point; 

 Passage Island. 



Olive Family (Oleaceae) 



Field Guide to the Genera 



Fruits seed-like with prominent wing at the tip, borne in loose drooping clusters 



fraxinus, p. 204. 



Fruits not winged, borne singly or in groups of several. 



Small shrubs up to about 1 foot high; leaves mostly linear or lance-shaped, 

 about 1/2 inch long, the lower broader and larger; fruits small capsules 

 menodora, p. 206. 



Large shrubs up to 5 or 10 feet high; leaves levcrse-egg-shaped or egg-shaped 

 to iance-shaped, mostly more than J/2 inch long; fruits like small olives 

 forestiera, p. 206. 



Ash (Fraxinus L.) 



Ash is well known as large trees usually found growing along streams 

 and in generally wet places. The shrub species found in our national parks 

 have a rather different appearance but can be identified as species of ash 

 because of their narrow wedge-shaped winged fruits hanging in loose clusters. 



Field Guide to the Species 



Leaves divided into 3 to 5 separate leaflets; flowers with white or greenish-white 

 corollas. 



