north american species of cactus(北美仙人掌)-第18章
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garden in 1893。
3。 Anhalonium furfuraceum（Watson）。
Mamillaria furfuraceaWatson； 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 pulvilligerumLem。 Cact。 （1839）。
Anhalonium elongatumSalm…Dyck （1850）。
This seems to be a third grooveless Mexican species。I have seen no
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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
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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 williamsiiLem。 Allg。 Gart。 Zeit。 xiii。 385 （1845）。
Anhalonium williamsiiLem。 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。
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