136 TREES OF THE NORTHERN UNITED STATES 
like, scaly, globular drupe, ripe in autumn. Bark scaling 
off like that of the Sycamore. 
1. Plénera aquatica, Gmel. (AMERICAN 
PLANER-TREE.) Leaves ovate-oblong, small, 1 
to 144 in. long, on short stems, sharp-pointed, 
serrate with equal teeth, smooth, green above 
and gray below, not oblique at base. Flowers 
minute, in small heads, appearing before the 
leaves. Fruit a scaly, roughened nut, 44 in., 
raised on a stalk in the calyx; ripe in Sep- 
tember. A small tree, 20 to 50 ft. high; wet 
banks, Kentucky and southward; hardy as far 
north as Philadelphia. 
P. aquatica. 
2. Pldnera acuminata. (Kiaxka ELM 
OR JAPAN PLANER-TREE.) Leaves large, 
glossy, smooth, deeply notched, on red 
stems; young shoots also red. This is a. 
larger, more hardy, and finer tree than the 
American Planer-tree, and should be more 
extensively cultivated. 
The Caucasian Planer-tree (Planera par- 
vifoha), with very small leaves, is also oc- 
easionally cultivated. 
Genus 76. CELTIS. 
Trees or shrubs with alternate, simple, 2-ranked, ob- 
lique, serrate leaves. Flowers inconspicuous, greenish, 
axillary. Fruit berry-like, sweet, edible drupes, about 
the size of a currant, with one seed; color dark; ripe in 
autumn, 
* Leaves usually sharply serrate........ 1. 
* Leaves almost entire ................ 2. 
1. Céltis occidentalis, L. (SuGARBERRY. 
HAacCKBERRY.) Leaves ovate, obliquely sub- 
cordate to truncate at base, long-acuminate, 
serrate (at least near the apex), rough above 
and hairy beneath. Fruit a single-seeded, 
¢. occidentalis. ¥ in., globular drupe, solitary on a peduncle, 
1 in. long, in the axils of the leaves; purple when ripe in autumn. 
