ECHINOFOSSULOCACTUS. 109 



without water; vegetation is here very scanty. This species is associated with other cacti 

 and with Agave lophantha, which it resembles in its habit more than it does that of its 

 own relatives. 



Illustrations: Palmer, Cult. Cact. 125; Curtis's Bot. Mag. 74: pi. 4393; Cact. Journ. 1: 

 149; Diet. Card. Nicholson Suppl. f. 515; Ann. Rep. Smiths. Inst. 1908: f. 23; Krook, 

 Handb. Cact. 30; Monatsschr. Kakteenk. 4: 9; Schumann, Gesamtb. Kakteen f. 5, 78; 

 Forster, Handb. Cact. ed. 2. f. 77; Engler and Prantl, Pflanzenfam. 3 6,J : f. 66; Cycl. 

 Amer. Hort. Bailey 2: f. 1269; Amer. Gard. 11: 464; Schelle, Handb. Kakteenk. f. 137; 

 Mollers, Deutsche Gart. Zeit. 25: 477. f. n, No. 5; 29: 90. f. 12; 91. f. 13; Garten-Zeitung 

 4: 182. f. 42, No. 9; 286. f. 66; Gard. Chron. 1873: 1116. f. 240; III. 29: f. 63; Belg. Hort. 5: 

 pi. 40; Stand. Cycl. Hort. Bailey 2: 610. f. 720; 4: f. 2139; Bliihende Kakteen 3: pi. 158; 

 Rumpler, Sukkulenten 192. f. 108; Goebel, Pflanz. Schild. 1: pi. 2, f. 1 ; Gartenwelt 5: no; 

 Watson, Cact. Cult. 186. f. 74; ed. 3. f. 51 ; Thomas, Zimmerkultur Kakteen 44; Remark, 

 Kakteenfreund 21. 



Figure 1 1 7 is copied from plate 4393 of the Botanical Magazine ; figure 1 1 ja is from a 

 photograph of a plant sent by Dr. Elswood Chaffey from Zacatecas, Mexico, in 1910. 



15. ECHINOFOSSULOCACTUS Lawrence in Loudon, Gard. Mag. 17:317. 1841. 



Mostly rather small plants, rarely over 10 cm. in diameter, but generally much smaller, usually 

 solitary, rarely clustered, deep-seated in the ground, globular or depressed, or very old plants 

 becoming short-cylindrie ; ribs usually numerous, in one species as few as 10, in others 50 to 100, 

 usually very thin, more or less wavy; areoles on each rib sometimes only 1 or 2, always felted when 

 young; spines in numerous clusters often covering the plant, some of them strongly flattened and 

 ribbon-like; flowers small, campanulate to subrotate with a very short tube; stamens numerous, 

 shorter than the perianth-segments; scales on the perianth and ovary few to numerous, scarious, 

 naked in their axils; fruit globular to short-oblong, bearing a few papery scales, these perhaps 

 deciduous in age ; seeds black with a broad basal truncated hilum. 



About 22 species, all native of Mexico, are here recognized, although more than three 

 times as many species of this relationship have been described in Echinocactus. From our 

 field observations the number of species must be larger than here recognized, but the 

 herbarium material is so scanty and the species already described are so many that for 

 the present we have contented ourselves chiefly in describing those which have been 

 illustrated or are represented by preserved material. 



Although this genus appears to be very distinct, the species are so little known that 

 we can give only a few of the characters. In the case of one plant which recently fruited 

 in the New York Botanical Garden the fruit splits down one side as in Pediocactus. This 

 may be a common character in the genus and should be looked for whenever possible. 



This genus was established by George Lawrence, gardener to the Rev. Theodore Wil- 

 liams at Hendon Vicarage, Middlesex, England, but so far has been overlooked by cata- 

 logues. We came upon it while looking through Loudon's Magazine of Gardening for 

 new cactus names. Its publication, however, had been observed and noted by that keen 

 bibliophile, James Britten (Journ. Bot. 54: 338. 1916). 



Lawrence numbers 35 species and varieties, most of which are named and briefly 

 described. The genus as he defines it is not a very natural one. He arranges the species 

 in three sections and each section is divided into two subsections. 



His first section, Gladiatorcs, corresponds to Schumann's subgenus Stenocactus of the 

 genus Echinocactus and represents Echinojossulocactus in our treatment, with Echinocactus 

 coptonogonus Lemaire as its type. 



The species belonging to his second section (Latispineae) and to his third section are 

 referred elsewhere as synonyms, except the following which we are not able to associate 

 with any of the names of Echinocactus: E. harrisii and E. ignotus-venosus. 



