264 PROCEEDINGS OF THE AMERICAN ACADEMY 



12. M. GXTMMiFERA, E. in Wisl. Rep, Similar to the last two, but 

 stouter ; flower larger, darker, but otherwise little different. Radial 

 spines 10 - 12 ; the lower ones much stouter and longer than the 

 upper ones : central spines 1 or 2, shorter. 



§ 5. LongimammcB, Salm. 



13. M. sPH^RicA, Dietr. : prolifera, csespitosa ; tuberculis ovato- 

 elongatis acutatis ; aculeis setaceis radialibus 12 - 14, centrali singulo 

 subbreviore vix robustiore ; floris magni tubo supra ovarium emer- 

 sum constricto elongate ; petalis flavis acuminato-aristatis. 



Hill-sides on the Rio Grande near Eagle Pass ; also Corpus Christi, 

 on the Gulf. — Single specimens clavate, but often forming dense 

 hemispherical masses. Tubercles 6-8 lines; spines 3-5 lines long. 

 Flower 1| -2 inches long. Fruit not seen. 



Subgen. 2. Coryphantha. Flores e basi tuberculorum hornotino- 

 rum aculeiferorum sulcatorum, vel in vertice ipso oriundi : ovarium 

 emersum. 



§ 1. AllifiorcB. 



14. M. PAPYRACANTHA, E. in PI. Fcndl. (Mem. Amer. Acad. 1849). 

 This interesting plant has been collected only in a single specimen, 

 near Santa Fe, which, together with the dried flowers, is in my pos- 

 session. Shape of tubercles not well distinguishable, doubtful whether 

 sulcate or not ; the lower ones proliferous. Spines compressed, flex- 

 ible, of the consistency of stiff paper ; 8 radiating and 3 or 4 central ; 

 the lowest one of these longest and broadest. Flowers white, central, 

 an inch or more in length and width. Fruit not seen. 



§ 2. FlavifiorcB. 



* Laxijlorce. (The originally central flowers are pushed aside by 

 the continuous development of new tubercles.) 



15. M. NuTTALLii, E. : simplex s. prolifera, csespitosa ; aculeis ra- 

 dialibus 10 - 17 setaceis rectis plerumque puberulis albidis, centrali 

 singulo robustiore ssepius deficiente ; sepalis fimbriatis et petahs flavi- 

 dis apice parce denticulatis lanceolatis, s. lineari-lanceolatis acutis ; 

 stigmatibus 2-8 erectis vel patulis ; bacca subglobosa tuberculis 

 breviore coccinea ; seminibus globosis scrobiculatis nigris. 



Var. a. BOREALis (M. Nuttallii, E. h c. Cactus mamillaris, Nutt. 

 Gen., 1818, non Linn.) : subsimplex ; aculeis setaceis 13-17 cum 

 centrali sajpe deficiente puberulis ; stigmatibus 2 - 5 ; baccis semini- 

 busq'ue minoribus. 



