G.74j CLASSIFICATION AND DESCRIPTION 133 
Baxus sempérvirens, L. (Boxwoop.) 
Leaves ovate, smooth, dark green; leaf- 
stems hairy at edge. This plant isa native 
of Europe, and in its tree form furnishes 
the white wood used for wood-engraving. 
Var. subfruticosa (dwarf boxwood) grows 
only a foot or two high, and is exten- 
sively used for edgings in gardens. 
The tree form is more rare in cultivation, 
and is of slow growth, but forms a round- 
topped tree. 
B. sempérvirens. 
ORDER XXXVI. URTICACEA. (NeErTLE Famtty.) 
A large order of herbs, shrubs and trees, mainly tropical. 
Genus 74. ULMUS. 
Tall umbrella-shaped trees with watery juice and alter. 
nate, 2-ranked, simple, deciduous, obliquely ovate to 
obliquely heart-shaped, strongly straight-veined, serrate 
leaves, harsh to the touch, often rough. Flowers insig- 
nificant, appearing before the leaves. Fruit a flattened, 
round-winged samara; ripe in the spring and dropping 
early from the trees. Bark rough with longitudinal ridges. 
* Leaves very rough on the upper side. (A.) 
A. Leaves 4 to 8 in. long; buds rusty-downy; inner bark very 
muUcilaginous: » gcc.cevessaesiees  Seevieaeseicess evs 1, 
A. Leaves smaller; buds not downy; cultivated. (B.) 
B. Wide-spreading tree; twigs drooping; fruit slightly 
MOPCHEG. cine y din Tigo gigeiewn adden Pum Wemaeas re 2. 
B. Tree rather pyramidal; twigs not usually drooping; fruit 
deeply NOtChed) ciwew csi sie tema aiaadscvagetes ve 3. 
* Leaves not very rough on the upper side. (C.) 
C. Buds and branchlets pubescent; twigs often with corky 
PIAS GS  sriicas ctisdsite ~ Ako debuntattnt) ea gna nena So eg A 
C. Buds and branchlets free from hairs, or very nearly sa. (D.) 
D. Twigs with corky wings. ..... 2... 6c. cee eee ees 5. 
D. Twigs often with corky ridges; cultivated ........... 2, 3. 
D. Branchlets never vorky............. ish nieee dubibare ee atin, VOL 
