424 : BOTANICAL GAZETTE [ DECEMBER 
which are oftenest confounded with Aralia, by the following 
characters: 
In Sassafras the primaries branch from the midrib, usually a 
considerable distance above the base, which is decurrent and 
never lobate; the margins are entire; the texture is not coria- 
ceous; sinuses margined, or secondaries at least showing some 
evidence of disarrangement in the region of the sinuses; second- 
aries camptodrome; the decurrent base usually margined. 
Sterculia has usually petiolate coriaceous leaves with obsolete 
venation and conically pointed lobes; is palmately lobed, usually 
from below the middle; primaries usually three from the top of 
the petiole; base cuneate; margins always entire; secondaries 
becoming effaced near the margin, or bowed close to the 
margin. 
In Platanus the leaves are large, thick, and palmately lobed, 
not deeply so, however, and the sinus always open; coarse leaves 
three-nerved from near the base; primaries and secondaries 
straight and stout; secondaries numerous, parallel, usually cras- 
pedodrome ; margin never entire; lobes always broad ; base some- 
times lobate. 
The American species of palmately lobed Aralias may be 
separated into five groups. 
SECTION 1. 
Thick leaves fan-shaped in outline with long thick petioles; 
young leaves three-lobed; old leaves five-lobed; lobes narrow 
and pointed; base decurrent (except A. Zaddacht); sinuses nar- 
row, extending more than half way to the base; margins dentate 
above with craspedrome secondaries, entire below with campto- 
drome secondaries; primaries three, stout, supra-basilar (except 
A. Zaddachi); \ateral primaries forking some distance from the _ 
midrib; secondaries numerous and parallel. Avalia digitata 
Ward leads the way to the Green River species, A. macrophylla 
Newb., and by its lobate basal expansion shows its close rela- 
tion to Platanus basilobata Ward. | 
This section includes: A. Saportana Lx., Dakota group; A. Saportana 
deformata Lx., Dakota group; Aralia sp., Dawson, Mill Creek; A. Welling- 
