ercles blunt or retuse）； 18 to 25 mm。 long and about as wide at base； the upper surface almost plane and smooth； except that it is more or less pulverulent and usually bears a small tomentose pulvillus （often evanescent later） just behind the claw…like tip： flowers rose…color： fruit elongated… oval and reddish。 （Ill。 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 Potosi （Eschanzier of 1891）： Mexico in general （specimens from Coll。 Salm…Dyck in 1858； Schott of 1858）： also specimens cultivated in Mo。 Bot。 Gard。 in 1881； also growing 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 cm。 long； white or pinkish； the sepals brownish。 Type； Pringle 2580 in Gray Herb。
At Carneros Pass； Coahuila。
Specimens examined： Coahuila （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 furfuraceum； 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 triangular portion would be about double its length。 The lower rim of the cup…like depression which terminates the tubercle 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 cm。 long by 2。5 cm。 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 （engelmanni） of the four or five known crossing the Rio Grande in the Great Bend。
3。 LOPHOPHORA； gen。 nov。
Depressed…globose； proliferous and cespitose； tuberculate…ribbed； unarmed plants： tubercles at first conical and bearing at summit a flower…bearing areola with a dense tuft or short pencil of compact erect hairs； when mature becoming broad and rounded （with the remnant of the penicellate tuft as a persistent pulvillus in a small central depression） and coalescing into broad convex vertical ribs： spine bearing areolae obsolete： flowers borne at the summit of nascent tubercles： ovary naked （that is free from scales； but often downy）： fruit and seed unknown。
These forms have been variously referred to Anhalonium and Echinocactus； but seem to deserve generic distinction。 They differ from Anhalonium in the entire suppression of the upper highly differentiated portion of the tubercle； in the broad and rounded development of the lower portion； and in the coalescence of the enlarged tubercles into broad vertical ribs。 In fact； in young specimens； the plant appears almost smooth； with shallow furrows radiating from the depressed apex。 The genus differs from Echinocactus in the suppression of the spine…bearing areolae； and the naked ovary。 In the examination of developing tubercles the relation to Anhalonium is evident。 In the latter genus the young tubercle bears on the summit of its pedicel…like lower portion the tufted flower…bearing areola the modified upper portion of the tubercle at that time appearing as a bract beneath the flower。 In Lophophora there is the same condition of things； except that the bract…like upper portion is wanting。 From this point of view it would appear that the differences between Lophophora and Echinocactus are intensified by the fact that the flower…bearing areola in the former genus is to be regarded as really lateral on a tubercle the upper part of which has disappeared。 This genus occurs abundantly in southeastern Texas； extending southward into Mexico。 Mrs。 A。 B。 Nickels reports that the Indians use the plants in manufacturing an intoxicating drink； also for 〃breaking fevers；〃 and that the tops cut off and dried are called 〃mescal buttons。〃
1。 Lophophora williamsii （Lem）。
Echinocactus williamsii Lem。 Allg。 Gart。 Zeit。 xiii。 385 （1845）。 Anhalonium williamsii Lem。 in Forst Handb。 Cact。 i。 233 （1846）。
Hemispherical； from a very thick root； often densely proliferous； transversely lined below by the remains of withered tubercles： ribs usually 8 （in young specimens often 6）； very broad； gradually merging above into the distinct nascent tubercles which are crowned with somewhat delicate penicellate tufts； which become rather inconspicuous pulvilli on the ribs： flowers small； whitish to rose： stigmas 4。 （Ill。 Bot。 Mag。 t。 4296） Type unknown。
Along the Lower Rio Grande； Texas； and extending southward into San Luis Potosi and southern Mexico。
End