]^ 1 2 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th 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 ; 

 VIII ; IX, fig. 2 ; X ; XI ; and XII. Endemic. 



O. Helleri K. Sch. in Rob. (1), 180.— Bindloe Isl. : ( ?), a 

 species of low Opimtia 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 



