the Embryos and Seedlings of the Cadaceae. 459 
(Genus Astrophytum. Treated under Echinocactus.) 
(Genus Malacocarpus. Treated under Echinocactus.) 
14. Genus Melocaetus. 
M. communis , Link and Otto. Figure in De Candolle, Revue, PI. VI. Also 
(as Cactus melocaetus') in De Candolle, Organographie, PI. XLVIII, Fig. 3. 
M. amoenus, Hoffmgg. Figure in Zuccarini. 
M rubens , Pfeiff. Figure in Pfeiffer, PI. XVI, Fig. 9. 
M. Lehmanni , Miq. Figure in Miquel, Monographia, PI. II. 
This genus includes nearly globular strongly-ribbed forms 
especially characterized by a strong cephalium. I have had 
no seeds, and the figures above cited are hardly detailed 
enough to allow conclusions to be drawn from them. All 
show a globular, or nearly globular, hypocotyl. M. amoenus 
in Zuccarini’s figure shows large thick pointed cotyledons, 
recalling the Ancistrocactus division; while M. rubens , as given 
by Pfeiffer, suggests rather Cephalocactus , an altogether un- 
likely difference between these two ; while M. Lehmanni , in 
Miquel’s picture, is different from the other two. De Can- 
dolle’s figure of M. communis is of interest in showing below 
the huge swollen stem, two projections which he mistook for 
cotyledons, but which, as Miquel 1 pointed out, are not so, 
but were probably two rootlets in that position. The nearly 
globular structure which he mistook for plumule is combined 
hypocotyl and epicotyl, with the cotyledons invisible. The 
presence of a lateral root in that position in Miquel’s figure 
of M. Lehmanni confirms this. The beginning of growth of 
the epicotyl shown by Miquel is insufficient to give a clear 
idea of it. 
1 5. Genus Leuehtenbergia. 
L.principis, Fisch. Figure 44. 
In this genus is but a single species, a rare and remarkable 
plant with very long, almost leaf-like, tubercles bearing papery 
1 Ann. Sci. Nat., Bot., 2nd Ser., XIV, 62, 63. 
