Nov. io, 1913 
Pubescent-Fruited Species of Prunus 
169 
kernel small, strongly flavored with prussic acid. Type specimen in United States 
National Herbarium, C. P. B. No. 1155. Merotypes cut from the tree that yielded the 
type specimen have been sent to a number of other herbaria. 
The type locality of Prunus eriogyna is along the watercourse in the 
boulder talus at the mouth of Tahquitz Canyon at the southern base of 
the San Jacinto Mountain, near Palm Springs, Riverside County, Cal. 
It is also found on dry 
talus slopes in Andraeas, 
Murray, and Palm Can¬ 
yons, along the trail to 
Van Deventer Flats be¬ 
low Santa Rosa Peak, 
and up the rocky slopes 
of the San Jacinto 
Mountains to an al¬ 
titude of over 2,000 
feet, growing in barren 
soil and crevices of 
rocks, being apparently 
extremely xerophytic. 
Its range is from the 
southern slopes of the 
San Bernardino Moun¬ 
tains southward along 
the desert slopes of the 
San Jacinto Mountains 
to San Diego County, 
and into Lower Cali¬ 
fornia. 
The plumlike appear¬ 
ance of the wood, es¬ 
pecially of the younger 
growth, and perhaps a sprinkling of roundish or oblong green pubescent- 
coated fruits, would excite an inquiry that would bring out the names 
“desert almond” or “wild apricot.” 
Fig. 5. —Prunus eriogyna , n. sp.: A , Section of calyx, X 3; B, detail 
of portion of calyx with petals, from outside, showing glandular 
dilation of lobes, X 3; C, twig showing angular habit of branching, 
leaves and fruit attached, H natural size. 
ADAPTATION TO DESERT CONDITIONS 
The adaptations of Prunus eriogyna to the peculiar conditions which 
prevail on the desert slopes of mountains are worth noting. The rain¬ 
fall, slight as it is, really governs plant activities, and vegetation becomes 
most nearly dormant during the summer months. The rains consist of 
rare torrential downpours in August and light rains from October to May, 
but are nearly confined to the period from December to March, the entire 
volume ranging from less than an inch to 9 inches and a fraction annually. 
With warm winter days and the temperature at night falling but little 
