STANDLEY TREES AND SHRUBS OF MEXICO. 981 



Seeds constricted above the base. 

 Flowers greenish or pinli. 



Flowers greenisli, 10 to 12 mm. long ; central spines yel- 

 lowish to reddish 120. N, annillata. 



Flowers pinlj, 20 mm. long ; central spines dark brown. 



121. N. fraileana. 



Flowers nearly white 122, N". swinglei. 



Seeds not constricted above the base. 



Central spines several; flowers yellowish 123. N. dioica. 



Central spines usually solitary ; flowers rose-colored. 



124. N. goodridgei. 

 Bristles none in the axils of the tubercles. 



Flowers rotate 125. N, zephyranthoides. 



Flowers campanulate. 

 Plants globose. 



Flowers white 126. N. carretii. 



Flowers pink to purplish. 



Inner perianth segments obtuse 127. N. jaliscana. 



Inner perianth segments acute to acuminate. 



128. N. bombycina. 

 Plants slender, elongate, and cylindric. 



129. N. occidentalis 



1. Neomammillaria g'aumeri Britt. & Rose, Cactaceae 4: 72. 1923. 

 Yucatan ; type from sand dunes of Progreso. 



Cespitose, the branches short, globose to short-cylindric, up to 15 cm. long; 

 tubercles dark green, short, nearly terete, obtuse, the axils naked even when 

 young, 5 to 7 mm. long, very milky ; spine areoles conspicuously white-woolly 

 at first, soon naked ; radial spines 10 to 12, spreading, acicular, white with 

 brown tips, or the lower ones in the cluster darker, 5 to 7 mm. long ; central 

 spine solitary, porrect, usually brown ; flowers very abundant from near the 

 top of the plant but not from the axils of young areoles, creamy white, 10 to 

 14 mm. long ; outer perianth segments greenish, brown-tipped ; scales on 

 flower tube broadly ovate, scarious ; fruit crimson, clavate, 18 to 20 mm. 

 long, naked. 



2. Neomammillaria petrophila (T. S. Brandeg.) Britt. & Rose, Cactaceae 



4: 78. 1923. 



Mammillaria petrophila T. S. Brandeg. Zoe 5: 193. 1904. 



Mountains of southern Baja California ; type from Sierra de la Laguna. 



Sometimes cespitose, milky, globular, 15 cm. in diameter or less ; tubercles 

 short, broad at base; spines at first chestnut-colored, becoming pale in age; 

 radial spines 10, about 1 cm. long, a little spreading; central spine 1 (rarely 2). 

 2 cm. long, darker and stouter than the radials ; flowers bright greenish yellow, 

 18 to 20 mm. long ; perianth segments hardly acute, sometimes slightly erose : 

 fruit small, roundish ; seeds reddish, smooth, less than 1 mm. long. 



3. Neomammillaria arida (Rose) Britt. & Rose. Cactaceae 4: 73. 1923. 

 Mammillaria arida Rose; Quehl, Monatsschr. Kakteenk. 23: 181. 1913. 

 Southern Baja California ; type from hills near Pichilinque Island, near 



La Paz. 



Plants usually single, globular, 3 to 6 cm. in diameter, containing much 



milk and giving it ofC freely when injured ; tubercles nearly terete ; radial 



spines about 15, pale, ascending, the bases sometimes yellowish and the tip 



dark ; central spines 4 to 7, 12 to 16 mm. long, much longer than the radials, 



79688—24 10 



