HOMALOCEPHALA. 



181 



Echinocactus subgrandicornis Haage (Forster, Handb. Cact. 347. 1846) is only a name. 



Echinocactus thelephorus (Hortus in Forbes, Journ. Hort. Tour Germ. 152. 1837) is 

 very briefly described and we can not identify the plant. 



Echinocactus verutum (Forster, Handb. Cact. 344. 1846), from Mendoza, was once 

 grown in English gardens. It is only a name. 



Echinocactus villiferus Scheidweiler (Forster, Handb. Cact. 347. 1846) is only a name. 



Echinocactus wilhehnii is listed by Schumann (Monatsschr. Kakteenk. 5: 108. 1895) as 

 from Hildmann's Catalogue. 



20. HOMALOCEPHALA gen. nov. 



Low, depressed or subglobose plants, strongly ribbed; spines stout; flowers central, rather large, 

 day-blooming; outer perianth-segments very narrow, pungent; inner perianth-segments narrow, 

 widely spreading; ovary covered with numerous linear pungent scales bearing in their axils masses 

 of white wool; fruit globular, scarlet, becoming naked, at first juicy, bursting irregularly ; seeds large, 

 black, smooth, reniform. 



The generic name is from SfxaXos level, 

 and K6(t>a\r) head, referring to the depressed 

 plant body. 



We recognize only one species, first 

 published as Echinocactus texensis Hopffer. 



1. Homalocephala texensis (Hopffer). 



Echinocactus texensis Hopffer, Allg. Gar- 



tenz. 10: 297. 1842. 

 Echinocactus lindheimeri Engelmann, Bost. 



Journ. Nat. Hist. 5: 246. 1845. 

 Echinocactus platycephalus Muhlenpfordt, 



Allg. Gartenz. 16: 9. 1848. 

 Echinocactus texensis gourgensii Cels in 



Labouret, Monogr. Cact. 196. 1853. 

 Echinocactus texensis longispinus Schelle, 



Handb. Kakteenk. 161. 1907. Fig. 192. Homalocephala texensis. 



Usually simple, sometimes globose, but generally much depressed, in large plants 30 cm. broad, 

 10 to 15 cm. high; ribs 13 to 27, very prominent, acute; areoles only 2 to 6 to a rib, densely white- 

 felted when young, large; radial spines usually 6, rarely 7, spreading or recurved, more or less flat- 

 tened, unequal, 1.2 to 4 cm. long, or rarely 5 cm. long, reddish, more or less annulated; central spine 

 solitary, longer than the radials, 3 to 6.5 cm. long, 3 to 8 mm. broad, much flattened, strongly annu- 

 late; flowers broadly campanulate, 5 to 6 cm. long and fully as broad, scarlet and orange below, pink 

 to nearly white above ; outer perianth-segments linear with more or less lacerate margins and ter- 

 minated by long spinose tips; inner perianth-segments with less pungent tip or without any, but 

 with strongly lacerate margins; filaments red; stigma-lobes 10, linear, pale pink; scales on the ovary 

 and flower-tube linear, pungent; fruit scarlet, globular, 16 to 40 mm. in diameter, nearly smooth 

 when mature, at first pulpy but becoming dry and apparently splitting open unequally; seeds large, 

 uniform, black, smooth, shining, somewhat flattened, angled on the back, 3 mm. broad; hilum lateral, 

 large, depressed; "embryo curved or hooked with the foliaceous cotyledons buried in the large 

 albumen" (Engelmann). 



Type locality: Texas; type grown in a botanical garden from seed. 



Distribution: Southeastern New Mexico, Texas, and northern Mexico. 



The flowers of this species open for four days in bright sunlight, closing at night; they 

 are delicately fragrant. 



This plant shows great variation in the size of the fruit and in the way it ripens and 

 dehisces the seeds. In 192 1 Mr. Robert Runyon sent us a box of very large fruits, almost 

 twice as large as any previously studied ; none of these fruits split open as it ripened. 



Dr. C. R. Ball writes of this plant as follows: "This plant is extremely abundant on 

 the high plains of western and northern Texas. In establishing farms in this section large 



