CACTACER. 89 
apart, in 4 rows when the branches appear acutely quadrangular, or in 5 rows when they are 
more terete. Radial spines 1-2 lines long, central one on lower part of joint wanting, or hardly 
longer than the radial ones, on the upper part 2-4 lines long. Flower about 3 inches long and 
of same width ; petals often reflexed, 4-6 lines wide. Fruit 6 or 8 lines long; seed between 
0.4 and 0.5 line long, much compressed, with a narrow hilum; its tubercles very much 
smaller than in the last species, Our plant bears a close resemblance to the last mentioned 
one, but may always easily be distinguished by the characters enumerated. 
18. C. ruprrosus, Poselger: e radice tuberosa tenuissimus, teres, lignosus, sursum sensim 
incrassatus, cylindricus, demum articulatus parceque ramosus, debilis, erectus seu geniculatus et 
reclinatus ; costis 8 vix prominulis ; areolis parvis confertis, junioribus parce sordide tomentosis ; 
aculeis 9-12 radiantibus parvulis subulatis albidis rectis adpressis, inferioribus paullo longiori- 
bus, centrali singulo e basi crassa subulato longiore toto seu versus apicem fusco sursum arrecto ; 
floris subterminalis (?) tubo brevi; pulvillis squamatis albo-lanatis aculeolatis ; sepalis superi- 
oribus 8 lineari-lanceolatis ; petalis 16 oblanceolatis acuminato-aristatis roseis patentibus ; fila- 
mentis brevibus ; stylo elongato ; stigmatibus 8 viridibus ; bacca subsicca villosa setosaque floris 
rudimentisque coronata ; seminibus minutis oblique obovatis comy is t lato-rugosi bi 
culatis. (Tab. LXIX, fig. 12.) 
On the Texan side of the Rio Grande, between Reynosa and Camargo, Dr. Poselger ; on the 
Chacon hills, 3 miles below Laredo, and also near Mier, on arid rocky ridges, always among 
shrubs, ‘‘ which support its weak and otherwise almost decumbent stem,’’ A. Schott.—Tuberous 
root globular, 3-14 inch in diameter; stem 1-2 feet high; lower part ligneous, ‘scarcely as 
thick as a quill; upper younger part and branches 4-8 lines in diameter ; young branches few, 
clavate ; ribs very little prominent ; areole 1-2 lines apart; radial spines a line long or less ; 
central spine 2-3 lines long, in weak specimens whitish, in robust ones the upper half or the 
entire spine brown or black, rigidly erect and appressed, generally reaching to the second areola 
above. The flower, which I have not myself seen, is described by Dr. Poselger in a letter as being 
terminal, ‘‘so that the ovary is a complete continuation of the stem.’’ I suppose that it rises 
from the upper, but certainly not the recent areole ; and that it cannot be truly terminal, i. e., 
a continuation of the axis, which would be in opposition to the character of the whole family. 
Schott also figures the plant as bearing fruit at the end of the branches, Flower over 2 inches 
long and of the same diameter, opening for several days, but only in bright noonday sunshine ; 
ovary and tube covered with very woolly pulvilli in the axils of reddish scales, with 6 or 8 
long white or black bristles ; petals rose-colored or purple, about an inch Jong. Fruit covered 
with long wool and black and white bristles, resembling very much that of C. cespitosus. 
Seed smaller than that of any other Cereus examined by me, only 0.4 line in the largest diame- 
ter, rugose from confluent tubercles which leave large pits between them. Albumen none; 
embryo almost straight, with distinct transverse cotyledons. Flower, fruit, and seed identify 
this species with the Echinoceret, thus furnishing another instance, if such were still needed, 
of the importance of the organs of fructification in the study and arrangement of the Cactacee, 
and of the fallacy of expecting the external shape of these plants to furnish characters for generic 
or subgeneric division. Without the knowledge of the flower and fruit, C. tuberosus would no 
doubt have been classed with the Cerei articulati, while in reality it is the slenderest Echino- 
cereus, connected with the ordinary ovate or globose forms through C. Berlandieri and C. pro- 
cu ; 
