12 CALIFORNIA ACADEMY OF SCIENCES  [Proc. 41H Ser. 
family found on the islands, which has red fruit and forms 
candelabra-like objects. 
The young of this species first appears as a flattened disk- 
shaped mass, dark green in color, and heavily covered with 
long rigid spines. This first articulation is followed by another 
above, which has its short axis at right angles to the corre- 
sponding axis of the articulation below, a process which is 
repeated until the plant has attained a height of 5-6 ft., when 
lateral branches, from which the crown of the tree is developed, 
are put out. In the meantime the articulations forming the 
trunk have been increasing in diameter, and as growth takes 
place more rapidly on the faces than on the edges of the articu- 
lations, the trunk soon assumes a more or less rounded form. 
The development is shown in Plates VII to IX. The trunk is 
heavily armed with long, ridged, and somewhat deflected 
spines, when the plant is in the young condition; but by the 
time the trunk has attained a diameter of a foot or more, most 
of these have been shed in the following manner. In the young 
segments the fascicles occupy deep pits in the surface. These 
pits extend into the cortical parenchyma from which the spines 
receive their nutrition. By the formation of periderm, inside 
of this, the nutrition is soon stopped and the spines drop off, 
remaining attached, however, for a considerable time after their 
physiological connection with the stem has ceased. The pits 
which contained the fascicles remain visible as slight indenta- 
tions through the greater part of the life of the plant. The 
bark is reddish-brown in color, and is made up of alternating 
layers of cork and stone cells which slough off in large sheets, 
one-half inch or more in thickness. After the disintegration 
of the layers of cork cells, the stone cells remain as loosely 
arranged plates somewhat resembling the ordinary shellac of 
commerce in general appearance. Much of the calcium oxalate 
is got rid of through the bark, as cross sections show a large 
number of rosette-like crystals of this salt. Plates VII, fig. 2; 
VT Xe ties Be; XT and: XAT, “Endemic: 
O. Helleri K. Sch. in Rob. (1), 180.—Brnp1ok Ist.: (?),a 
species of low Opuntia occurs on this island, which is very 
similar in general appearance to the one on Tower and Wen- 
man Ids. It is very likely the same. CULPEPPER IsL.: owing 
to the fact that the low Opuntias which occur on this island are 
