ROSACEAE. 131 
PRINSEPIA. 
(Family Rosaceae). 
Shrubs, with rather short su- 
pra-axillary spines somewhat con- 
stricted at base: deciduous. Twigs 
long and slender, round: pith 
moderate, round, yellowish, cham- 
bered or finally hollowed out ex- 
cept for annular lines about the 
cavity. Buds solitary (or the 
spine representing a_ second), 
small, indistinctly scaly, con- 
cealed in brown hairs that line the 
stipules and fill the axil, the end- 
bud lacking. Leaf-scars alter- 
nate, small, half-round, raised: 
bundle-trace 1: stipules rather 
large becoming firm and persistent 
at top of the swollen leaf-cush- 
ion. 
Prinsepia, unlike most Rosa- 
ceae, which have solid pith, has 
its pith chambered or finally ex- 
cavated, as Solereder indicates in his Systematic Anatomy of 
the Dicotyledons. Mention of this discovery is made in a pa- 
per on chambered or discoid pith by Foxworthy in the Pro- 
ceedings of the Indiana Academy of Science for-1903. It is 
one of a small group differing in a number of respects from 
other Rosaceae. 
Some Prinsepias are sometimes called Plagiospermum, but 
the two genera are not considered sufficiently distinct for 
segregation by other botanists. They are among the earliest 
shrubs to come into leaf in spring. 
Twigs becoming brown. (1). P. sinensis. 
Twigs persistently gray. (2). P. uniflora, 
