NEOMAMMILLARIA . 



67 



Key to Species — continued. 



DD. Axils of tubercles with bristles as well as wool (33-53). 



E. Some of spines much elongated, curved, and fiexuous. 



Definite central spines wanting 34. N. compressa 



Central spines present. 



Central spines weak 35 . N. mystax 



Central spines stiff 36. N. petterssonii 



EE. None of spines elongated, or if elongated, not fiexuous. 

 F. Tubercles terete or nearly so. 



G. Axils of tubercles bearing j-ellow wool 37. N. eichlamii 



GG. Axils of tubercles bearing white wool. 

 H. Spines all radial. 



Spines 5 or 6, in young plants sometimes only 4 38. N. karwinskiana 



Spines always 4 39. N. praelii 



HH. Spines both radial and central. 



I. Radial spines numerous, 12 or more. 



Central spines reddish, not much longer than the 

 radials. 



Outer perianth-segments ciliate 40. N. slandleyi 



Outer perianth-segments setose 41. N. evermanniana 



Central spines elongated, usually white except at tip. 



Flowers yellow 42. N. parkinsonii 



Flowers dark red 43. N. geminispina 



II. Radial spines few, 5 to g. 



Spines black when young 44. N. pyrrhocephala 



Spines at most brownish. 



Flowers yellow 45. N. woburnensis 



Flowers pinkish 46. N. collinsii 



FF. Tubercles strongly angled. 



G. Spines both radial and central. 



Radial spines numerous 47. N. chinocephala 



Radial spines few, bristle-like. 



Central spines 4 to 6 48. iV. tenampensis 



Central spines 2 49. N. polygona 



GG. Spines few, all of one kind. 



Flowers yellow 50. N. confusa 



Flowers rose-colored or white. 

 Flowers rose-colored. 



Plants globose; stigma-lobes 4 or 5 51. N. villifera 



Plants cylindric; stigma-lobes 8 52. N. polyedra 



Flowers white 53. N. conzattii 



CC. Milk-tubes developed, if at all, only in stem; tubercles not milky (54-80). 

 D. Central spines wanting. 



Spines subulate; areoles elliptic 54. iV. napina 



Spines mostly acicular; areoles circular. 



Spines numerous 55. A'', lanala 



Spines few (4 to 6). 



Spines 5 or 6, short, straight 56. N. kewensis 



Spines 4, elongated, curved. 



Flowers large (2.5 cm. broad) 57. N. suhpolyedra 



Flowers small. 



Spines long and weak 58. N. galeotlii 



Spines subulate 59. N. telracantha 



DD. Central spines present. 



E. Central spines usually 2, sometimes solitary. 

 F. Radial spines 20 or more. 



Central spines stout and not very long; stigma-lobes white. 



Plant round or nearly so at apex; central spine often i 60. N. elegans 



Plant strongly umbilicate; central spines always 2 61. N. psetidoperbella 



Central spines long 62. N. dealbata 



FF. Radial spines 20 or fewer. 



Radial spines white, bristle-like. 

 Stigma-lobes red. 



Globose or somewhat elongated 63. iV. haageana 



Depressed-globose 64. N. perbella 



Stigma-lobes white. 



Radial spines appressed 65. N. collin'a 



Radial spines not appressed 66. TV. donatii 



Radial spines brownish when young, stouter than in the last 67. iV. mundtii 



EE. Central spines usually 4, sometimes more. 

 F. Central spines white or yellow. 

 Radial spines white. 

 Plant globose. 



Axils of tubercles not setose; central spines usually 4 68. N. celsiana 



Axils of tubercles setose; central spines usually 9 69. iV. aureiceps 



Plant cylindric. 



Plants from Yucatan 70. N. yucatanensis 



Plants from Central America 71. N. rueslii 



