CACTACEH OF THE BOUNDARY. 177 
Semina minuta, plerumque rugulosa seu scrobiculata, rarissime verruculosa, vix levia, fulva, fusca, seu nigra. 
fost Mamillarie heretofore known and cultivated belong to this subgenus, which is well characterized by the 
lateral position of the flowers 
1. M. MICROMERIS, sp. nov.: parvula, aa globosa, vertice depresso; tuberculis minimis verruceformibus 
edteaaeatatie® ; areolis solum fueniae lana laxa longa vestitis ; aculeis plurimis pluriserialibus minutis ex albido 
cinereis, in plantis junioribus et in aerate inferioribus sthaudiack adultarum sub-20 zqualibus lineam longis 
radiantibus, in tuberculis floriferis (verticem plantz adulte versus) 30-40 stellato-porrectis, superioribus 6-8 czteros 
bis terve superantibus versus apicem clavatis acutis, parte superiore demum deciduo; floribus minimis subcentralibus ; 
sepalis petalisque 5; stigmatibus 3 stamina eequant ntibus ; bacca elongata clavata coccinea floris rudimenta dejiciente ; 
gia cacy oblique obovatis basi acutis uigris lucidis sub lente levissime verruculosis, hilo elongato ventrali.? 
(Tab. I. and II. fig. 1-4 
Var. - GreEGGII: major, tuberculis globoso-ovatis paullo majoribus; aculeis rigidis 2-3 seriatis, interioribus [4] 
5-7 brevioribus robustioribus, exterioribus a paullo longioribus, omnibus radiantibus ; seminibus paullo 
minoribus leviter verrucosis. (Plate IT. figs. 5- ‘ 
From El Paso to the San Pedro iver; mene in a single locality east of this river ; in naked places on mountain tops 
or sides, only on limestone, never in the porphyritic region: C. Wright. Var B. was collected by the late Dr. J. Gregg 
mountain ridge between Azufrora and Penos Bravos, near Saltillo, Mexico. — Small globose plants, depressed at. 
top, simple, or very pag! ‘(and probably only after an injury to the top of the main plant) branching. Heads usually 
3 to 1 inch in diamet largest specimens seen 15-18 lines in diameter. ta rine covered by the delicate 
aitiygrey spines. Tubereles about } line long, only 1-1} lines distant from o r, older ones shedding the 
spines, and giving th e plant a very pretty tuberculated seipekrai': ; in the ar plants 21 or 34 spiral 
rows of the tubercles are the most distinct. Spines not pungent in several series, usually about 1 line long e on the 
younger tubercles of the fully-developed plant a I suppose, which may bear flows wers in their axils) the 6-8 upper 
exterior spines are 2-3 or sometimes even 4 times as long as the other spines (2-4 lines long), thickened or nin 
toward the end, with an acute point. These err are the first to appear in the nascent tubercle (as indeed is the case 
in all iManséllarte where the uppermost radial spines are always developed before the others), suid with loose wool 
of almost the same length. These elongated superior spines form a small tuft in the vertex of the plant, which 
includes and partly hides the flowers uid fruit. en they get older, apparently after the second or third year, the 
upper part of these long spines breaks off, leaving them of the same length as the others, but always distinguishable 
by their ie end, These peculiar spines, of which I have not seen any analogy in other species, are wanting in 
younger plan 
e nee of the flowers in this plant is rather a doubtful one. I have not seen living specimens in flower ; 
but the structure of the tuft, the position of the berries in the dead specimens before me, and the note of Mr. Wright, 
“ flowers central,” would seem to indicate that they really appear in the new growth of the same season. 
red and small-tubercled Coryphantha. 
this species would be an anomalous small-flowe 
In that case 
But Iam yet inclined to con- 
sider the flowers as only nearly ee Bo borne in the axils of the last tubercles of the preceding season ; all the 
of o 
analogies, at least, are in favor 
Cactacee, namely, — 3-5 sepals, hea - eer two or three times as man 
plant being a true Mamillaria. Flowers es to the simplest type of 
and a style with 3 stigmata ; 
nam stam 
diam: ais of flower about 3 lines; petals whitish or very light pink. Fruit an anes clavate red and somewhat 
juicy berry, 4-6 lines in length, without the remains o 
shrivelling up ; obovate, grey, 
the seed always in such a peers that the 
the cotyledons 
(produced by the always more or less distinct compression of 
the seed) toward the beholder, the base below, and the ventral 
part or edge of the seed to the left, and the dorsal part to the 
right. 
The hilum is large or small, circular, eto oval, or elon- 
gated, mostly more or less basal, rarely su pangs 
or ventral, It is usually surrounded by pyaar rim, forme 
by the thickened testa, smoother than oa other ange of the 
seed. The alb when present, or the trace of it, — 
which is indicated by a never-wanting thickening of the en- 
dopleura, — is always found on the ventral part of the seed. 
and hid in the tuft :°so it is found in the specimens brought home. 
of the flower on top, somewhat persistent on the plant, finally 
Seeds only 6-12 in 
The back or dorsal part of the seed is often more or less cari- 
nate, especially toward the base. e testa of the seed is 
i Spaces yellowish or brownish or black; or it is 
rustaceous, and then teed: black ; or it is whitish, 
pat thick and bony (only in Opunt iw). *he surface of the 
seed is smooth, often shining; or. it is is rugose, er pitted, or 
covered xe “7 minute or larger warts or tubercles. These 
tinct, or more or less concatenate or confluent, 
leaving irregular pits in their interstices. 
inoceret ; while 
pr known in our Flora generally have owt seeds. Of 
the quite peculiar, large, flat, and red seeds of Opuntia, 
find occasion to speak hereafter 
