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the desert region of western Arizona and adjacent California； Nevada； and
Utah。In the former region is found the widespread viviparus； which
extends from the southern borders of British America to the plains of
eastern Colorado and western Kansas； and even crosses the Rocky
Mountain divide into northern Idaho and northeastern Washington； and
missouriensis； which also ranges from the high prairies of the Upper
Missouri to the same southern limit； and is continued southward into
Texas in its varieties similis and robustior。
In the Arizona desert region； four distinct but closely allied forms have
become differentiated from the strong radiosus stock； viz。： arizonicus；
deserti； alversoni； and chloranthus； all of which might be regarded as
distinct species。In southeastern Texas is found an isolated form； sulcatus；
occurring between the Brazos and Nueces rivers。That viviparus must be
regarded as a strong northern extension of the radiosus stock can not be
doubted； as the low depressed cespitose northern form seems to merge
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southward so gradually into the simple more robust ovate to cylindrical
forms of radiosus as to suggest the propriety of regarding them all as
specifically identical。
The result of a closer inspection of the distribution of these nearly
related forms is worthy of note。C。 viviparus extends from British America
and the Upper Missouri to eastern Colorado and western Kansas； neo…
mexicanus （the form most nearly related to viviparus） extends from central
Colorado and southern Utah into Mexico； at the southeastern edge of this
range begins radiosus and extends eastward through southern Texas； from
the western edge of neo…mexicanus the form arizonicus extends westward
into southern California； touching chloranthus at its Utah limit； and at its
California extension reaching alversoni and deserti； the latter of which
extends northward into the desert region of southeastern California and
adjacent Nevada。Taking this type as of Mexican origin； it seems to have
entered the United States from Sonora and Chihuahua； and to have spread
in three directions； viz。： eastward through southern Texas； westward and
northwestward into southern California and southern； Utah； and northward
to the head waters of the Missouri and British America； though we would
limit the northern extension of the present specific type to central
Colorado； and would regard the still more northern forms as of the same
origin but entitled to specific rank。
2。 ANHALONIUMLem。 Cact。 Gen。 Nov。 （1839）。
Depressed or flattened； simple； unarmed plants； covered with peculiar
imbricated tubercles above and their scale…like remains below： tubercle
with lower and upper parts very different； lower part comparatively thin
and flat； upper exposed part triangular in outline and divergent； very thick
and hard； the lower surface smooth and keeled； the upper surface plane or
convex； smooth or tuberculate or variously fissured； with a broad wool…
bearing groove or simply a more or less evident tomentulose apical areola：
spine…bearing areola obsolete： flower…bearing areola at the summit of the
lower peduncle…like portion of the very young tubercle （thus appearing
axillary with reference to the exposed part of the tubercle） and bearing a
dense penicellate tuft of long soft hairs which conceals the lower part of
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North American Species of Cactus
the flower and the entire fruit and persists about the apical region of the
plant as matted and apparently axillary wool： ovary naked： seeds large；
black； and tuberculate： embryo obovate； straight。
According to the present views concerning generic limitations in
Cactaceae； Anhalonium must certainly be kept distinct from Mamillaria；
and to such a view Dr。 Engelmann had finally come。The generic
distinction is based upon such characters as （1） the complete suppression
of the spine…bearing areolae； （2） the strong differentiation of the tubercles
into two very distinct regions； （3） the production of the flower at the apex
of the basal or penduncle…like portion （which becomes flattened and
expanded at maturity） of a very young tubercle； and （4） the large
tuberculate seeds。
In the case of engelmanni the broad woolly groove of the upper
portion of the tubercle expands below into the flower…bearing areola； but
terminates blindly above just behind the sharp apex。In prismaticum and
furfuraceum the groove is obliterated； but there usually remains a small
（more or less tufted） areola and depression just behind the apex to mark its
upper extremity。This apical areola therefore； does not represent a spine…
bearing areola； but the closed upper extremity of a tubercle groove。
It seems evident that Anhalonium is a much modified Cactus； and that
its affinity is with the coryphanths； through such a species as C。
macromeris； in which the flower becomes extra…axillary。If in macromeris；
with the flower standing well up on the tubercle； the portions of the
tubercle above and below the flower should become very different from
each other； the upper portion being so much modified as to cause the
spine…bearing areola to be obliterated； the condition of things in
Anhalonium would be obtained。
* Upper surface of tubercle with a broad and deep wool…bearing
longitudinal groove which widens below。
1。 Anhalonium engelmanniLem。 Cact 42 （1839）。
Mamillaria fissurataEngelm。 Syn。 Cact。 270 （1856）。Anhalonium
fissuratum Engelm。 Bot。 Mex。 Bound。 75 （1859）。
Depressed globose or flat； top…shaped below and tapering into a thick
root； 5 to 12 cm。 in diameter： tubercles （upper portion） appressed…
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imbricate； 12 to 18 mm。 long and about as wide at base； the upper surface
convex and variously fissured （presenting an irregular warty appearance）
even to the edges： flowers apparently central； about 2。5 cm。 long and
broad； shading from whitish to rose： fruit oval； pale green； about 10 mm。
long： seeds 1。6 mm。 long。 （Ill。 Bot。 Mex。 Bound。 t。 16）Type unknown； but
specimens of Wright； Bigelow； and Parry in Herb。 Mo。 Bot。 Gard。 are the
basis of Engelmann's Mamillaria fissurata。
On limestone hills； in the 〃Great Bend〃 region of the Rio Grande in
Texas； and southward into Coahuila。Fl。 September…October。
Specimens examined： Texas （Wright of 1850； Bigelow of 1852； Parry；
with no number or date； Lloyd of 1890； Evans of 1891； Briggs of 1892）：
also growing in Mo。 Bot。 Gard。 1893。
This species is very closely related to the Mexican A。 kotchubeyi Lem。
（A。 sulcatum Salm…Dyck）； but unfortunately no type of that species seems
to be in existence； and Dr。 Engelmann notes （Mex。 Bound。 Rep。 75） that
〃it seems no living or dead specimen is at present extant in
Europe。〃Judging from the description； the upper surface of the tubercles in
A。 kotchubeyi； aside from the central furrow； is smooth； at least the margin
is 〃very entire。〃
** Upper surface of tubercle not grooved； but usually with atomentose
pulvillus at the tip。
2。 Anhalonium prismaticumLem。 Cact。 1 （1839）。
Mamillaria prismaticaLem。 Hort。 Univ。 i。 231 （1839）。Cactus
prismaticusKuntze； Rev。 Gen。 Pl。 261 （1891）。
Flat above； top…shaped below； 7。5 to 12。5 cm。 in diameter： tubercles
（upper portion） close＇y imbricate but squarrose… spreading； sharply
triangular…pyramidal and very acute （with a sharp cartilaginous tip； which
usually disappears with age and leaves the older tubercles blunt or retuse）；
18 to 25 mm。 long and about as wide at base； the upper surface almos