ERICACEAE. 289 
EPIGAEA. Trailing Arbutus. 
(Family Ericaceae). 
Prostrate and rooting small 
shrubs with finally exfoliating 
bark: evergreen. Twigs slender, 
terete: pith moderate, rounded, 
continuous, brown. Buds solitary, 
or the inflorescence-buds quickly 
multiple and conical-ovoid with 2 
hairy outer scales and a number 
of smooth very acute inner scales. 
Leaf-scars linear when cataphyls 
have fallen, or usually lacking, the 
leaves falling only with the cor- 
tex: stipule-scars lacking. Leaves 
elliptical-ovate, often cordate, en- 
tire but usually ciliate. 
Like blueberries and rhododen- 
drons, the _ popular’ fragrant- 
flowered May-flower or trailing 
arbutus requires a certain acidity 
of the soil for its successful cul- 
tivation; but, as Coville has shown, 
it is capable of successful growth as a compact full-flowered 
potted plant if given the proper soil conditions. 
This sensitiveness of Ericaceae to the condition of the 
soil has been shown to be connected with the fact that their 
roots grow in a sort of mutually helpful parasitic relation- 
ship with certain fungi, which themselves are prevented from 
thriving unless the soil is too acid for the growth of most 
bacteria. An interesting discussion of the question is given 
by Coville in Bulletin 193 of the Bureau of Plant Industry at 
Washington. 
Twigs very red-bristly. E. repens. 
