460 Ganotig . — The Comparative Morphology of 
spines and flowers at their summits. The germination and 
early stages have not been described. I have obtained 
seeds from Mr. William Tell, of Austin, Texas, who obtained 
them from a correspondent in Mexico ; and as living plants of 
this species have come from the same source, the identifica- 
tion is to be trusted. The embryo (Fig. 44) is altogether 
Echinocactus-Wke , with the pointed cotyledons so characteristic 
of that genus. The hypocotyl is deep red in colour though the 
first leaves of the epicotyl are white, an unusual feature. 
The epicotyl develops first two leaves at right angles to 
the cotyledons, which bear spine-clusters in their axils, and 
both leaves and clusters are soon carried up on the tops of 
strongly developed cylindrical tubercles, which, except for 
those of Anhalonium , are larger than those of any Cactaceae 
I have seen, and this fact is in itself confirmation of the 
identity of my seeds as of this species. A third tubercle then 
develops at right angles to the first pair, and later a fourth. 
The spines are also Echinocactus- like, much feathered with 
hairs, and very different from those of the adult plants, and 
this feature persists into seedlings of considerable size, as 
I have seen in a specimen formerly described by me 1 . At 
this writing my specimens have not advanced beyond the 
stage shown in the figure 44 c, but I hope to obtain from this 
material the full life-history of this most remarkable of the 
Cactaceae. But all features show its close connexion with 
Echinocactus , though I cannot say with which division. The 
nearest approach to the remarkable tubercles of the epicotyl 
that I have seen is in E. bicolor , which has large spirally- 
arranged tubercles, though they are not so large as in Leuch- 
tenbergia . 
1 6. Genus Mamillaria. 
M. elephant idem, Lem. Figure 45. 
M. latimamma , DC. Figure in Goebel, p. 86. 
M. radio sa neo-mexicana, Engelm. Figure 46. 
M. centricirrha , Lem. Figure in Schumann, in Engler and Prantl, p. 170. 
3 Flora, op. cit., p. 74. 
