RUTACEAE. 161 
ZANTHOXYLUM. Pricxly Ash. 
(Family Rutaceae). 
Small trees or shrubs, aromatic 
or pungently acrid, usually armed 
with detachable prickles which 
sometimes occur paired at the 
nodes: deciduous. Twigs moder- 
ate’ or stout, subterete: pith 
rounded, continuous, very creamy 
white. Buds moderate, super- 
posed, sessile, globose, woolly and 
indistinctly scaly. lLeaf-scars al- 
ternate, broadly triangular or 3- 
lobed, little raised, sometimes with 
a conspicuous articular mem- 
brane: bundle-traces 3: _ stipule- 
scars lacking. Winter-character 
= references under Hvodia. 
Har \ The strong prickles beside the 
4 aN leaf-scar in Zanthoxylum present 
ty a puzzling question as to their 
= [Ip il morphology. If they represent 
stipules, they should be called 
spines: if they are superficial outgrowths of the cortex, they 
_ are truly prickles. Position is not a safe guide. The pungent 
outgrowths of gooseberry and rose are prickles: they are sti- 
pules in the locust, and, like other stipules, are connected 
with the vascular system of the stem at least in their early 
stages. They are believed to be prickles in Zanthoxrylum. 
1. Prickles broad and acuminate. (1). Z. Bungei. 
Prickles not acuminate even when widened. 2. 
2. Nodal prickles often widened: articular-membrane 
conspicuous: buds red-rusty. (2). Z. americanum. 
Prickles not greatly dilated nor articular-membrane 
developed: buds glabrous. (3). Z. Clava Herculis. 
