48 RoBINSON : SPINES OF FOUQUIERIA 
In /dria, another genus of the same family, a similar spine, 
originating in the petiole of the leaf, has been described by Poisson 
(Bull. Mus. Hist. Nat. 1: 278. 1895) and in some species of the 
nearly related Cantua, of the Polemoniaceae, there is a woody ridge — 
at the base of each node. The latter, however, is more like the 
structure which protects the axillary bud in Syringa and Philadel- 
phus than the spines of the Fouguzeriaceae. 
The majority of the buds in the axils of the primary leaves do — 
not elongate to form branches, but develop small clusters of spat- | 
ulate leaves which are almost sessile and do not form spines — 
(Fics. 11 and 12, ¢). 3 
Engelmann (Bot. Gaz. 8: 338. 1883) was the first to call 
attention to this peculiar mode of dehiscence of the leaves of Fou- — 
Fic. 10. Fouguieria a oe showing a, manner of dehiscence of leaf; hy 
manner in which spine and bark may be peeled from stem. - 
11. Young shoot of MISES patie ¢, cluster of secondary leaves; — 
WwW, hicianes which will form spine. : 
Fic. 12. Young shoot of Fouguieria splendens : 
1G. 13. Spine of Fouguieria Macdougalii. a surface from which upper portion | 
of petiole has separated. : 
guerta. Plank (Garden & Forest, g: 73. 1896) says: “ The — 
bases of the spines appear to arise in the cellular part, leaving the 
wood full of holes in their decay,”” which statement was doubtless 4 
made because of the peculiar growth of the cork between the — 
spines and the portions of the outer tissues, which adhere to 
them, making the spines, with their adhering pieces of bark, dry. 
papery structures, which still have close enough contact with the 
adjacent cells to leave a scar when they drop off. Van Tieghe™ 
