180 E/MPETRACEAE. 
EMPETRUM. Crowberry. 
(Family Empetraceae). 
Low spreading shrubs with ex- 
foliating bark: evergreen. Twigs 
slender, ridged below the leaf- 
scars: pith minute, continuous. 
Buds solitary, sessile, compressed 
round-ovoid, with 2 or 3 exposed 
scales, very minute except for the 
flower-buds in the upper axils. 
Leaf-scars subverticillate, minute, 
half-round, somewhat raised: 
bundle-trace 1, indistinct: stipule- 
sears lacking. Leaves small, el- 
liptical-oblong, revolute to a hairy 
groove, entire. 
The winter-characters of Hm- 
petrum nigrum are given by 
Bosemann, 35; and Fant, 53. 
Solereder figures a _ cross-section 
of its leaf in his Systematic Anat- 
omy of the Dicotyledons, 2:800, 
f. 188. 
The type of inrolled leaves that Empetraceae and certain 
Ericaceae possess has been shown by Gibelli’s developmental 
studies to differ essentially from the usual type of revolute 
leaves which are merely rolled backward for a distance from 
the margin. Here, the grooves at either side of the midrib 
develop in such a manner as to make them morphologically 
elongated pits rather than merely covered parts of the nor- 
mal lower leaf surface. 
Glabrate. °: 1D) tends AMP UI. 
Tomentose. . BE, nigrum andinum. 
