epithelantha. 
93 
of the position of the flower, however, which is at the spine-areole, the genus is better 
referred to the sub-tribe, Echinocactanae, where in the genera Lopliophora and Ariocarpus 
we have a similar fruit. 
Mr. Charles Wright, in his field notes, first called attention to the central position of 
the flower of Mammillaria micromeris, and Engelmann, who discussed it (Cact. Mex. 
Bound. 4) in some detail, was in doubt as to its position. Dr. Weber seems to have been 
the first to determine the exact position of the flower and, recognizing its significance, 
proposed a new generic name for it, but he also referred it to Echinocactus and in still 
another place left it as a Mammillaria. 
1 . Epithelantha micromeris (Engelmann) Weber. 
Mammillaria micromeris Engelmann, Proc. Amer. Acad. 3: 260. 1856. 
Mammillaria micromeris greggii Engelmann, Proc. Amer. Acad. 3: 261. 1856. 
Cactus micromeris Kuntze, Rev. Gen. PI. 1: 260. 1891. 
Cactus micromeris greggii Coulter, Contr. U. S. Nat. Herb. 3: 101. 1894. 
Mammillaria greggii Safford, Ann. Rep. Smiths. Inst. 1908: 531. pi. 4, f. 1. 1909. 
Plants small, simple or cespitose, nearly globular, but depressed at apex, 6 cm. in diameter or 
less; tubercles very low, small, arranged in many spirals, 1 mm. long; spines numerous, white, the 
lower radials about 2 mm. long, the upper radials on the young tubercles 6 to 8 mm. long and con- 
nivent over the apex, narrowly clavate, the upper half finally falling off; flowers from near the 
center of the plant in a tuft of wool and spines; flower very small, whitish to light pink, 6 mm. 
broad; perianth-segments 8 to 10; stamens 10 to 15; stigma-lobes 3; fruit 8 to 12 mm. long; seed 1.5 
mm. broad. 
Type locality: Western Texas. 
Distribution: Western Texas and northern Mexico. 
Writers generally, as well as dealers of these plants, 
are disposed to treat the large forms of this species as a 
variety, var. greggii, but we have observed no reason 
except size for this conclusion. The large form seems to 
extend throughout the range of the species proper. In 
June 1921, Mrs. S. L. Pattison sent us from western Texas 
an unusually large plant which was nearly 8 cm. high and 
6 cm. in diameter. 
The plant is known as button cactus. Its fruits, called 
chilotos, are slightly acid and are edible. 
The names Epithelantha micromeris Weber and Echinocactus micromeris Weber, although 
both mentioned by him (Diet. Hort. Bois 804. 1898), were not formally published. 
Mammillaria micromeris fungifera (Monatsschr. Kakteenk. 19: 140. 1909) is only a 
catalogue name. 
Pelecyphora micromeris Poselger and Hildmann appears as a synonym of Mammillaria 
micromeris in Garten-Zeitung 4: 322. 1885. 
Illustrations: Cact. Mex. Bound, pi. 1; 2, f. 1 to 4; Cact. Joum. 1: 43; pi. [2] for 
February in part; Riimpler, Sukkulenten 200. f. 115; Diet. Gard. Nicholson Suppl. 514. 
f. 545; Forster, Handb. Cact. ed. 2. 267. f. 26, 27; Cycl. Amer. Hort. Bailey 1: 203. f. 302; 
Stand. Cycl. Hort. Bailey 5: f. 3016; Amer. Garden n: 460; Monatsschr. Kakteenk. 20: 
126; 29: 81; Schelle, Handb. Kakteenk. 248. f. 166, 167; Garten-Zeitung 4: 323. f. 76; 
Watson, Cact. Cult. 167. f. 65; ed. 3. f. 42; Blanc, Cacti 71. f. 1394, as Mammillaria 
micromeris; Cact. Mex. Bound, pi. 2, f. 5 to 8; Blanc, Cacti 71. f. 1395, as Mammillaria 
micromeris greggii; Ann. Rep. Smiths. Inst. 1908: pi. 4, f. 1, as Mammillaria greggii. 
Figure 102 shows a plant in fruit, collected by Dr. Rose at Langtry, Texas, in 1908 
(No. 11612). 
