202 
TRANS. OF THE ACAD. OF SCIENCE. 
slightly ciliate; 18-21 petals, rose red, with a deeper colored 
streak, lance-linear, • shorter and narrower than the inner 
sepals, entire; stamens not half as long as petals, with oval 
anthers; style much longer than stamens, with 5-6 short, 
greenish yellow suberect stigmas. 
Mamillaria bicolor , Lehm., is not a Texan plant, as has 
been stated, inadvertently, in Synops. p. 7.. Dr. Poselger 
found it on another Rio Grande, between Tampico and Real 
del Monte, Mex. 
Mamillaria papyracantha , Eng., is an Echinocactus, as 
stated above. 
Mamillaria recurvispina, Eng., in Cact. Mex. Bound., p. 
12 ; Syn. p. 10. As there' is already a species named thus 
by Vriese, (see Walp. Rep. 2, p. 801,) I now name the Ari¬ 
zona species M. recurvata. M recurva , Lehm., is a form of 
M. macracantha , D.C., fide Salm. 
Cereus variabilis , thus named in Cact. Mex. Bound., p. 40 
t. 60, f. 5-6, and in Synops. p. 31, is not Pfeiffer’s plant, 
figured in Abbild. 2, t. 15, but seems to be, as regards fruit 
and seeds, identical with a species obtained by Dr. Poselger 
near Tampico, and decided by him to be C. princeps , Hort. 
Wurzb. ex-Pfeiff Enum. p. 108. Plants from the Rio Grande 
have repeatedly bloomed here at the late Mr. Grieve’s, and 
as the flower has never been described, I here supply the 
omission. Fruit and seed, obtained near Matamoras, have 
been described and figured in Mex. Bound. Cact. 1. c. 
Flores ad apicem caulis ramorumve pauci magni albi noc- 
turni; ovario ovato areolis aculeolatis 25-30 stipato; tubo 
elongato cylindrico sursum sensim ampliato areolis 16-20 vix 
squamigeris, inferioribus aculeolatis munito; sepalis superi- 
oribus 20-25 lanceolatis patulis reflexisve; petalis 40-50 
pluriseriatis lineari-lanceolatis patentissimis; staminibus su- 
periori tubi parti gradatim adnatis; stigmatibus 12-13 in 
capitulum clavato-obovatum coarctatis pallide virescentibus. 
In bloom from July to September, flower 7-8 inches 
long, 5^-6 inches wide; tube 4-5 inches long; lower sepals 
near the well defined upper edge of the tube reddish green, 
3-9 lines, upper ones petaloid, 9-18 1. long; petals 2 inches 
long, and about 41. wide; lower part of tube for 2 or 2 \ 
inches, with a naked, nectariferous surface; the upper part, 
2§-3 inches, densely beset with'stamens of about equal length, 
so that the mass of the. anthers form a deep funnel,, corres¬ 
ponding to the shape of the upper part of the tube; the outer 
series of stamens forms a regular crown, but is not separated 
from the inner lower ones by a naked belt, such as is found 
in many species; nor are the filaments declined, and, so to 
say, fasciculated. This is interesting, as it weakens the value 
of this arrangement of stamens as a generic or subgeneric 
character; nevertheless, it is one of the few general charac-- 
