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pulverulent and usually bears a small tomentose pulvillus (often eva- 
nescent later) just behind the claw-like tip: flowers rose-color: fruit 
elongated-oval and reddish. (Jil. Lem. Cact. t. 1.)—Type unknown. 
Referred to Mexico in general, but reported definitely only from San 
Luis Potosi. Undoubtedly found in Coahuila, and possibly crosses the 
Rio Grande in the region of the “ Great Bend.” 
Specimens examined: SAN Luis Porost (Hschanzier of 1891): MEx- 
Ico in general (specimens from Coll. Salm-Dyck in 1858; Schott of 
1858): also specimens cultivated in Mo. Bot. Gard. in 1881; also grow- 
ing in same garden in 1893. 
3. Anhalonium furfuraceum (Watson). 
Mamillaria furfuracea Watson, Proc. Amer. Acad. xxv. 150 (1890). 
Very closely related to prismaticum; but triangular portion of tubercle 
acuminate and shorter, having an irregularly mamillate upper surface, 
and the acumination ending abruptly in a cartilaginous depression 
containing a tomentose pulvillus: flowers 2.5 to 3 em. long, white or 
pinkish, the sepals brownish.—Type, Pringle 2580 in Gray Herb. 
At Carneros Pass, Coahuila. 
Specimens examined: CoaHuma (Pringle 2580 of 1889). 
The type of this species was not among the collections received from Cambridge, 
but a specimen of the same distribution from the National Herbarium shows tubercle 
dimensions different from those recorded in Dr. Watson’s description. In that 
description the triangular terminal surface is said to be “about an inch broad by 
one-half inch,” which is decidedly different from the equilateral surface of the tubercle 
of prismaticum. In the National Herbarium specimen of furfuraceu m, however, of the 
same distribution, the surface is almost equilateral, measuring 15 mm. long by 18 
mm. wide at base. Without the acuminate upper portion the breadth of the triangu- 
lar portion would be about double its length. The lower rim of the cup-like depres- 
sion which terminates the turbercle and contains the pulvillus is sometimes slightly 
prolonged into a tooth, which in prismaticum becomes the sharp tip of the tubercle. 
The ‘minutely furfuraceous-punctulate” character of the tubercle is common to all 
the species of Anhalonium I have seen, and simply represents the external openings 
of the remarkably long cuticular passageways to the stomata. 
4. Anhalonium pulvilligerum Lem. Cact, (1839). 
Anhalonium elongatum Salm-Dyck (1850). 
This seems to be a third grooveless Mexican species. I have seen 
no specimens, but judge from the description that it differs from the 
two preceding species chiefly in its less crowded and more elongated 
tubercles (triangular portion 5 em. long by 2.5 em. broad at base) 
which are covered at apex with a tomentose pulvillus. 
? 
GEOGRAPHICAL DISTRIBUTION, 
This curious genus is strictly Mexican, and, so far as at present 
recorded, is characteristic of Coahuila, but a single species (engel- 
mannt) of the four or five known crossing the Rio Grande in the Great 
Bend. 
