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. 



