34 



CACTACEOUS PLANTS. 



the fronds in some species of Cibotinm, In the Eew museum are good 

 specimens of the substance. Cultivated plants are 8 to 10 inches high, of 

 globular form, with twenty to twenty-one ridges 1 to IJ inch deep, spirally 

 arranged. The clusters of spines are half an inch apart, and contain twelve 

 to fourteen grey spines 1 inch long. 



B. LONGIHAMATTJS, Galeotii. — Eemarkable for the length of the spines 

 which give it a very peculiar appearance. It is also interesting for a 

 character which may probably have some bearing on the fertilisation. It 



1^''^)\ 



ri3 6 — Echmocactus rhoclophtlialmns 



is well described by Engelmann as follows :— " The flowers form a groove 

 juBt above the spines, separated from the spiniferous areolae by two to 

 live obtuse cylindrio glandular bodies, which often exude a clear Tiscous 

 liquid. I find them also in E. setispinus, E. Emoryi, and numerous others 

 and they correspond no doubt with the glands in the groove of Mamillaria 

 Schesii and others. They appear with the flower, and are soft and fleshy- 



