ECHINOMASTUS. 



147 



According to Mr. E. C. Rost, for whom the plant is named, this species extends from 

 the western fringe of the Imperial Valley, California, almost to Jacumba and down Lower 

 California for about 40 miles . 



Mr. Rost's note on a plant sent to the New York Botanical Garden is as follows: 



"This cluster of yellow-spined plants shows in the main plant 

 the appearance of being wrapped in straw. All of the mature plants 

 of this variety have the same peculiarity. Note that the young off- 

 shoots of this specimen show a number of bright red spines, which 

 disappear in the mature plants. One specimen I found to be 8 feet 

 in height as shown in photograph. Some of the plants are single, 

 but many are clustered." 



This is a very striking plant, perhaps nearest F. acan- 

 tliodcs, but with a much more slender stem, and more 

 appressed spines and these straw-colored. 



The type is based on a plant collected in Lower Cali- 

 fornia, 40 miles south of the International Boundary Line 

 (Rost, No. 327). 



Figure 1536 is from a photograph taken by E- C. Rost 

 at the type locality in 1921. 



DESCRIBED SPECIES, PERHAPS OF THIS GENUS. 



Echinocactus haEmatacanthus Monville in Weber, Diet. Hort. 

 Bois 466. 1896. 



Echinocactus electracanthus haematacanthus Salm-Dyck, Cact. Hort. 

 Dyck. 1849. 150. 1850. 



Fig. 1536. Ferocactus rostii. 



Simple, sometimes perhaps proliferous, short-cylindric, 5 dm. high, 3 dm. in diameter; ribs 

 12 to 20, stout, light green ; spines all straight, reddish with yellowish tips, the radials 6, the centrals 4, 

 3 to 6 cm. long; flowers funnelform, 6 cm. long, purple; scales of the ovary round, white-margined; 

 fruit ovoid, 3 cm. long. 



Type locality: Not cited. 



Distribution: Between Puebla and Tehuacan, according to Weber. 



We do not know this species and our description is based on Weber's. His differs 

 from the original where the central spine is described as solitary and reflexed. Schumann 

 does not seem to have understood this species, as he first placed it after E. pilosus. Echi- 

 nocactus gerardii Weber (Diet. Hort. Bois 466. 1896) is referred here by Schumann but it 

 seems never to have been described. 



Echinocactus rafaelensis Purpus, Monatsschr. Kakteenk. 22: 163. 191 2. 



In clusters of 8 to 10, globose to short-cylindric, light green, at the apex slightly depressed and 

 woolly; ribs 13 to 20, prominent; areoles elliptic; radial spines 7 to 9, 3 cm. long, the upper ones some- 

 what connivent ; central spine solitary, 4 to 6 cm. long; flowers and fruit unknown. 



Type locality: Minas de San Rafael, San Luis Potosi, Mexico. 

 Distribution: Known only from the type locality. 



We do not know this species and place it here on the statement of Quehl, who writes 

 that it is similar to E. robustus and E. flavovirens. 



Illustration: Monatsschr. Kakteenk. 23: 35, as Echinocactus rafaelensis. 



17. ECHINOMASTUS gen. nov. 



Plants small, globular or short -eylindric, ribbed, the ribs low, more or less spiraled, divided into 

 definite tubercles; areoles bearing several acicular spines with or without stouter central ones; 

 flowers central, medium-sized, borne at the spine-areoles, usually purple; fruit small, short-oblong, 

 scaly, becoming dry, dehiscing by a basal opening; scales few, their axils naked; seed large, muricate, 

 black, with a depressed ventral hilum. 



