to add species to the C. scolymoides group without the fullest
information.

Prince Salm-Dyck refers C. scolymoides to "M. daimonoceras Lem.
Cact. gen. nov., p. 5," but no mention of such a name can be
found in the work referred to. Labouret refers C. corniferus to
the same name and reference. If "M. daimonoceras" was anything
more than a garden or herbarium name used by Lemaire I have been
unable to find it, and Dr. Engelmann's notes indicate that his
search met with the same result. It is possible that the name
was applied loosely to this assemblage of closely related forms
that seem to cluster about C. corniferus.

A most perplexing question of relationship is presented by the
forms that have been called pectinatus, scolymoides, sulcatus
(calcaratus), Echinus, and the Mexican forms radians,
impexicomus, corniferus. It may be that they are all merely
varieties of one strong polymorphic type, but our knowledge of
corniferus is so incomplete, and material of other forms is so
scanty, that I can not venture to make such an assertion.
However, it seems probable that radians, pectinatus, scolymoides,
sulcatus and Echinus all have green fruit, while in impexicomus
and corniferus it is red. It has also seemed proper to merge
radians and pectinatus, also impexicomus and corniferus, and to
refer sulcatus to scolymoides as a variety. These seven forms
are thus reduced at least to four species.

49. Cactus scolymoides sulcatus (Engelm.).

Mamillaria sulcata Engelm. Pl. Lindh. 246 (1845), not Pfeiff.