CACTACEiE OF MEXICO SAFFOKD. 561 



terminating in small spine-bearing areoles. The spines vary greatly 

 in form, occurring in radiating starlike groups, with or without a cen- 

 tral spine, pectinate or comblike, or long and wiry. In some species 

 they are as fine as hairs, in others they are stout and clawlike ; some are 

 straight, others curved like fishhooks ; some are smooth, others hairy, 

 and others plumose or feathery. They are divided by Schumann into 

 four groups: (1) Coryphantha, in which the flowers issue from near 

 the center or apex of the plant and the tubercles have a longitudinal 

 groove uniting the flower-bearing and spine-bearing areoles; (2) Dol- 

 icothele, in which the tubercles are long and ungrooved and the flow- 

 ers issue from the axis of the tubercles; (3) Cochemiea, occurring 

 on the peninsula of Lower California and in Chihuahua; and (4) 

 Eumamillaria, or Mamillaria proper. These are usually regarded 

 as subgenera, but they may be worthy of generic rank. 



(1) Coryphantha is divided into two series: Aulicothelse, in which 

 the tubercles are without glands, as in Mamillaria durangensis^ M. 

 macromeris, M. scheerii, M. elephantidens (pi. 14, fig. 3), J/, conoidea 

 (pi. 14, fig. 1) ; and Glanduliferse, in which circular red or yellow 

 glands are present in the axils of the tubercles or under the areoles, 

 including Mamillaria macrothele and M. erecta. 



(2) Dolicothele, with comparatively large yellow flowers and 

 bristlelike or needlelike spines radiating from the terminal areole 

 of the long tubercle, is composed of the two species Mamillaria 

 sphcerica, of Texas, and the closely allied M. longimammu, of Mexico 

 (pi. 14, fig. 2), both of which contain poisonous alkaloids. 



(3) Cochemiea, characterized by large flowers with exserted sta- 

 mens, is represented in northern Mexico by the single species Mamil- 

 laria senilis^ with many white, bristle like radial spines and several 

 dark-colored hooked central spines, and with large orange-colored 

 flowers, occurs amid the snow of the high mountains of Chihuahua. 

 M. roseana occurs at La Paz and on Carmen Island, where it was col- 

 lected by Dr. Edward Palmer; and M. pondii on Cedros Island, where 

 it was collected by Lieut. Charles F. Pond, U. S. Navy. 



(4) Enmamjillaria. — This division is composed of two groups, the 

 first including plants with watery sap, called by Schumann " Hydro- 

 chylus," the second with plants containing milky or gummy latex, 

 called " Galactochylus." 



Among the species included in the section Hydrochylus are Mamil- 

 laria micromens^ M. greggii (pi. 4, fig. 1), M. leona (pi. 2, fig. 3), 

 M. Candida^ M. pusilla (pi. 2, fig. 4), M. hocasana (pi. 4, fig. 4), M. 

 glochidata, M. plumosa (pi. 3, fig. 6), and M. grahamii, M. carretii 

 (pi. 4, fig. 2). 



Among the species included in the section Galactochylus are Mamil- 

 laria elegans, M. celsiana, M. heyderi (pi. 9, fig. 1), M. inelanocentra^ 



