6o THE CACTACEAE. 



Riimpler, Sukkulenten 208. f. 118; Gartenflora 34: 25; Watson, Cact. Cult. 189. f. 75; ed. 



3. f. 52 ; Cycl. Amer. Hort. Bailey i : 203. f. 303 ; Stand. Cycl. Hort. Bailey 2: f. 718; Illustr. 

 Hort. 5: pi. 186; Forster, Handb. Cact. ed. 2. 237. f. 21; Cact. Joum. i: 107, 149; Krook, 

 Handb. Cact. 34; Ann. Rep. Smiths. Inst. 1908: pi. 14, f. 6; Palmer, Cult. Cact. 117; 

 Schelle, Handb. Kakteenk. 275. f. 197; Monatsschr. Kakteenk. 29: 81 ; Weinberg, Cacti 23; 

 Knippel, Kakteen pi. 28; Mollers Deutsche Gart. Zeit. 25: 477. f. 11, No. 3; Garten- 

 Zeitung 4: 218. f. 50; Blanc, Cacti 78. No. 1710; West Amer. Sci. 11: 8; Bait. Cact. Joum. 

 1 : 89 ; 2 : 164; Floralia 42 : 369 ; Remark, Kakteenfreund 22 ; Haage, Cact. Kultur ed. 2. 206. 



Figure 56 is reproduced from a painting made by Miss E. I. Schutt in 1907, of a plant 

 sent from San Luis Potosi in 1905 by Dr. E. Palmer. 



11. PHELLOSPERMA gen. nov. 



A globular to cylindric, usually cespitose cactus with a large, fleshy, branched root; tubercles not 

 grooved above, not milky; flowers borne in axils of old tubercles, funnel-shaped; fruit globular to 

 cylindric, red, depressed at apex; seeds large (for this group), dull black, not pitted but rugose, with 

 a thick corky base nearly as large as the body. 



Type species: Mammillaria tetrancistra Engelmann. 



This genus differs from all its relatives in its very peculiar seeds. The flower, in its 

 shape and origin, suggests the following genus, but in its color and size resembles Cory- 

 phantha radiosa. A single species is known, native of the western United States. 



The generic name is from 0eXX6$ cork, and airepi^a seed, referring to the corky base of 

 the seed. 



1. Phellosperma tetrancistra (Engelmann). 



Mammillaria tetrancistra Engelmann, Amer. Journ. Sci. II. 14: 337. 1852. 

 Mammillaria phellosperma Engelmann, Proc. Amer. Acad. 3: 262. 1856. 

 Cactus phellospermus Kuntze, Rev. Gen. PI. i: 261. 1891. 

 Cactus tetrancistrus Coulter, Contr. U. S. Nat. Herb. 3: 104. 1894. 



Solitary or cespitose, cylindric; sometimes becoming very large and then 3 

 dm. long, usually very spiny; root elongated, carrot-shaped or sometimes 

 branched; tubercles terete, often elongated, their axils naked; radial spines numer- 

 ous, acicular, white or sometimes with a brown tip, not pungent; central spines i to 



4, stouter and longer than the radials, often brown or black, one or all strongly 



hooked; flower 3.5 to 4 cm. long, purple; base of tube slender, greenish, naked; pj^, ^^ seed of 



scales and outer perianth-segments ciliate; style and stigma-lobes cream-colored; phellosperma 



fruit rather variable in size, sometimes 3.7 cm. long, becoming dry in age, with a tetrancistra. 



depressed umbilicus; seeds black, dull, 2 mm. long. 



Type locality: San Felipe, California. 



Distribution: Western Arizona, southeastern California, southern Utah, and southern 

 Nevada; probably northern Lower California. 



Mr. C. R. Orcutt, under date of March 5, 1922, comments on the distribution of this 

 plant as follows: 



"It reaches its greatest development on sandy and gravelly slopes near the White Water River 

 east of Banning, California. It no doubt enters Lower California, for I believe that I have found it 

 within a mile of the boundary Une. It is comparatively rare in Arizona." 



We have seen no specimens from Utah, but suspect that the plants from that state 

 which have been referred to Alammillaria gralianiii probably belong here. The species 

 should be looked for in northern Lower CaUfornia and Sonora. 



Illustrations: Cact. Mex. Bound, pi. 7; Engler and Prantl, Pflanzenfam. 3*'': 162. f. 

 56, B; Cact. Joum. 1: pi. for February; Bol. Direccion Estudios Biol. 2: f. 3; Monatsschr. 

 Kakteenk. 20: 167, as Mammillaria phellosperma. 



Figure 58 is from a photograph of a plant sent from California in 192 1 by E. C. Rost; 

 figure 57 shows a seed taken from a plant sent by Loren G. Polhamus in 192 1 from Bard, 

 California. 



