FROM MISSOURI TO SANTA FE AND NORTHERN MEXICO, 43 
A careful examination of the seeds of numerous Cactaceew, has indicated to me two principal 
- divisions in that family: 1. Cotyledons, more or less distinct, directed with their edges to the edge 
(or towards the umbilicus), and with their faces to the flattened side of the seed; when curved, 
accumbent. 2. Cotyledons, mostly very distinct, foliaceous, directed with their edges to the faces, 
and with their faces to the edges of the seed (or towards the umbilicus) ; when curved, incumbent, 
and often circular or spiral. 
The first class comprises Mamillaria, with a straight embryo; and doubtless, also, [92 (8) ] 
Melocactus, seeds of which, however, have not been examined by me; and Echinocactus, 
mostly with a curved embryo. The second class includes Echinocereus, with a nearly straight 
embryo, and very short cotyledons; Cereus, with a curved embryo, and foliaceous incumbent coty- 
ledons (probably also Echinopsis and Pilocereus, and perhaps Phyllocactus and Epiphyllum) ; Opuntia, 
with a circular or spiral embryo (circular and with a larger albumen in all Opuntia cylindracee ; 
spiral and with a much smaller albumen in all Opuntia elliptice examined by me), and very large 
cotyledons. Rhipsalis and Pereskia may also belong here, but were out of my reach. 
The flowers of all the species belonging to the first class, with the exception of some Mamii- 
larie, make their appearance on the growth of the same year. Those of the second class produce 
the flowers always upon the growth of the next preceding or former years. The first class may, 
therefore, be distinguished by the name of Cactacew parallele (from the direction of the cotyledons), 
or C. apici flore (from the position of the flowers). The second class can be named, in a cor- 
responding manner, Cactacece contrarie, or C. lateriflore. 
Echinocereus is principally distinguished from Cereus proper by its low growth ; its short, more 
or less oval stems, which are frequently branching at base, and thereby cespitose; by the diurnal 
flowers, with short tubes; by the nearly straight embryo, with short cotyledons. From Zchinopsis, 
to which some species have been referred, it differs also by the short-tubed diurnal flowers, and by 
the numerous filaments being adnate to the lower part of the tube. For further particulars compare 
the note 7. The species of Echinocereus inhabit Texas and the northern parts of Mexico, where 
Ceret proper are very rare. They extend even farther north than the Echinocacti ; but appear to be 
excluded from the old limits of the United States, where the cactus family is represented only by 
some Opuntie and Mamillarie. The southern limits of the Echinocerei are unknown to me, but 
I doubt whether they extend far in that direction; the nearly-related ZHchinopses, on the contrary, 
appear to be exclusively inhabitants of South America, especially the La Plata countries. 
As I am speaking of the geographical distribution of the Cactacew, I may as well add here that 
Mamillarie were found ihroaghodt the whole extent of Dr. Wislizenus’s tour, and that at least four 
species occur in Texas. Echinocacti were observed only south of Santa Fé, and from there to 
Matamoros, but none on the highest mountains, which were occupied by Opuntie, Mamillarie, 
and Echinocerei ; two Echinocacti have been found in Texas. Only two species of true Cerei were 
seen; one of a peculiar type about Chihuahua, and another near the mouth of the Rio Grande, which 
does not appear to differ from the wide-spread C. variabilis, Pfeiff. Opuntia elliptica, as well as cylin- 
dracee, were observed from New Mexico to Matamoros, and species of both are also found in Texas. 
Melocacti, Phyllocacti, and other genera of Cactacew, not mentioned above, were not met with. 
The notes and collections of Dr. Wislizenus confirm the opinion of that acute observer and 
successful cultivator of Cactacee, Prince Salm-Dyck, viz.: that most species of this family have a 
me limited geographical range, the most striking exception being those belonging to the genus 
puntin. 
On the same day two other species of Echinocereus were found in pine timber, both [93 (9) ] 
with beautiful deep red flowers.2 We shall have occasion to speak of others hereafter. 
° EcHINOcEREUS TRIGLOCHIDIATUS, n. sp.: ovato-cyJindricus, 6-7-costatus, costis undulatis acutis; areolis 
sparsis, orbiculatis, junioribus albo-lanatis ; sams 3-6, plerumque 3, rectis compressis angulatis, cinereis, sub-deflexis ; 
