CACTACEAE (CACTUS FAMILY) 327 



panulate or funnel-shaped, from the axils of the tubercles, fully open in sun- 

 light and only for a few hours. Ovary often hidden between the bases of the 

 tubercles and naked, as is also the exserted succulent berry. 



Flowers yellowish-green; central spine mostly solitary, or wanting. 



Plants simple (single) ......... 1. M. missquriensis. 



Plants caespitose 2. M. similis. 



Flowers red or purple; central spines 3-12. 



Central spines about 4, brown . . . . . . . 3. M. vivipara. 



Central spines 3-1 2, purple 4. M. neomexicana. 



1. Mamillaria missouriensis Sweet, Hort. Brit. 171. 1827. Globose, 3.5 

 cm. in diameter, simple or nearly so: tubercles ovate-cylindrical, 12-14 mm. 

 long, slightly grooved: radial spines 13-17, straight, whitish, setaceous, 

 somewhat unequal, 8-10 mm. long; central spine more robust, straight and 

 porrect, puberulent, 10-12 mm. long, often wanting: flowers about 2.5 cm. 

 long, yellow or reddish: stigmas 2-5: fruit globose, scarlet, 6-8 mm. in diam- 

 eter: seeds globose, black and pitted, 0.8-1.1 mm. in diameter. On the 

 plains; Montana to Kansas and Colorado. 



2. Mamillaria similis Engelm. Bost. Journ. Nat. Hist. 5: 246. 1845. 

 Closely related to the preceding but caespitose, with 12-15 puberulent ra- 

 dial spines, the central very often wanting, larger flowers (2.5-5 cm. long), 

 fruit and seeds (1.6-2.2 mm. in diameter), and 5 stigmas. Colorado (?) to 

 Oklahoma and Texas. 



3. Mamillaria vivipara (Xutt.) Syn. Succ. Suppl. 72. 1819. Low and 

 depressed-globose, usually proliferous and caespitose (forming large masses), 

 but sometimes simple: tubercles terete and loose, lightly grooved: radial 

 spines 12-20, stiff and white, often dark-tipped, 6-8 mm. long; central spines 

 usually 4, brownish, 8-12 mm. long, 3 spreading upwards, the lowest stouter 

 and shorter and deflexed: flowers about 3.5 cm. long and even broader when 

 expanded, bright purple: stigmas pointed with a short mucro: fruit oval, pale 

 green, juicy, 12-18 mm. long: seeds yellowish-brown. On the foothills and 

 eastern plains of the Rocky Mountains, from the Canadian border to Colorado. 



4. Mamillaria neomexicana (Engelm.) A. Nels. Globose to short-cylin- 

 drical, simple or branched from the base, only a few cm. high: radial spines 

 12-40, white with dusky apex; centrals 3-12, purplish: flowers 3-5 cm. long 

 and about as broad, violet to dark purple: seeds obovate, pitted, less than 

 2 mm. long. [Cactus radiosus neomexicanus (Engelm.) Coult. Rev. N. A. Sp. 

 Cactus, etc., 120. 1894.] Utah and Colorado, southward and eastward to 

 Mexico. 



2. ECHINOCACTUS Link & Otto 



Mostly larger plants, globose or depressed, or ovate, or rarely subcylindric, 

 simple or very rarely caespitose. The spines on the more or less vertical ribs. 

 Flowers contiguous to and above the spines (on the new growth of the plant, 

 often from the nascent woolly areolae and therefore more or less vertical). 

 Ovary covered with sepaloid scales w r hich are naked or woolly in their axils. 

 Fruit succulent (edible) , or sometimes dry, covered with the persistent scales, 

 sometimes enveloped in copious wool, and usually crowned with the persistent 

 remnants of the flower. 



Stems with tubercles, mostly in spiral rows. 



Radiating spines fewer than 10; centrals fewer than 5 . . . . 1. E. glaucus. 



Radiating spines more than 10; centrals more than 5 . . . .2. E. Simpsomi. 

 Stems with vertical and definite ridges 3. E. Whipplei. 



1. Echinocactus glaucus K. Sch. Gesamth. Kakteen 438. 1899. Simple, 

 sometimes proliferous, depressed-globose or ellipsoidal: ribs entirely broken 

 up into glaucous tubercles arranged in about 8-13 rows: radial spines 8 or 9, 

 centrals 1-3: flowers rose-color: ovary scaly, glabrous. Colorado. 



2. Echinocactus Simpsonii Engelm. Trans. St. Louis Acad. 2: 197. 1863. 

 Subglobose or depressed, turbinate at base, simple, often clustered, 7.5-12.5 

 cm. in diameter: ribs 8-13, only indicated by the spiral arrangement of the 



