36 
CA CTACE2E. 
Upper central spines 3 or sometimes 4, 2-3 inches long, bulbous and angular at base, terete 
above ; lower central spine l|-2^ inches long, flattened. Spines on fruit 3-8 lines long, fewer 
and stouter than in the other form. 
Cereus Engelmanni , Parry, has been found abundantly by Mr. A. Schott on the lower Gila ; 
a specimen brought home evidently seems to unite them, and consequently C. variegatus and 0. 
chrysocentrus are to be considered forms of it. 
I am acquainted with the habitus of about 15 or 16 species of the subgenus EcurNOCEREUS. All 
of them are of low growth, (I write of those only with which I am acquainted,) never more than 
12, seldom more than 8, and often less than 5 inches in height. All, also, are more or less 
cespitose, or branching from the root; some of them slightly, others very much so. Cereus 
viridiflorus, chlorantlms, dasyacanthus, ctenoides, ccespitosus, longisetus, Fendleri, gonacanthus, 
hexcedrus, paucispinus, and Engelmanni, grow in small irregular tufts, or masses, some of the 
joints or stems being much taller than others. Some of them, such as C. viridiflorus, dasya- 
canthus, ctenoides, ccespitosus, and Fendleri, are often nearly simple, or having but few branches ’ 
while others, such as C. chlorantlms, longisetus, gonacanthus, hexcedrus, paucispinus , and Engel¬ 
manni, have usually 8-20 joints. C. poly acanthus, pliceniceus, and enneacanthus are much 
branched, and grow in somewhat flattened masses, sometimes with a circular outline, but not 
always, all the joints being of nearly an equal height. C. stramineus always forms a dense 
hemispherical mass, of a perfectly regular contour—the central joints being the oldest and 
longest—9-12 inches high, gradually subsiding towards the circumference of the mass until the 
extreme outer stems are not more than 2 inches high. C. Mojavensis often grows similarly, 
but I have also seen it in much broader masses, containing 500-800 heads or joints ; in such 
cases it is always flat f ened on the top. Where this state occurs, the central joints are as high 
as in the hemispherical masses, but the hemispheric contour is destroyed by the longitudinal 
extension of the joints, forming masses sometimes 4 or 5 feet in diameter. C. pliceniceus and 
C. conoideus, two forms which Dr. Engelmann has united into sub-species, are quite different 
in tbeir manner of growth. C. pheniceus, as stated above, grows in irregular flattened masses, 
while C. conoideus has the more elevated and somewhat hemispherical shape of C. stramineus . 
On account of the unfavorable season of the year (October—March) during our journey through 
regions of these cacti, we were unable to procure the flower or fruit of any of these plants. In 
our friendly correspondence with Dr. Engelmann, I insist that C. phceniceus and C. conoideus 
are distinct species, and (from analogy only) I assume that when the flower of C. conoideus is 
obtained, it will be found to be a purple, while that of C. pliceniceus is crimson. Time and 
observation, however, are the only decisive arbiters of such controversies. 
Subgen. Eucereus. 
Of Cereus proper only one species was seen, viz : 
11. Cereus giganteus, Englm.: Williams’ river to the Colorado of the west, February 4 to 
February 22, 1854. This is the most northern true Cereus that we have, being found as high 
as latitude 34°, while Cer Greggii and Emoryi are found only a little above latitude 32°. 
This plant has a considerable range, extending south, from this place to near latitude 28° 
in the vicinity of Guaymas Sonora. The fruit under the Mexican name of Pitajaya, pronounced 
Pit-a-zi-ah or Pit-ai-yah, is a great source of sustenance to the Mexicans and Indians of the 
regions where it grows. Conserves and molasses, or syrup, are made from them which are 
preserved during the winter season for future use. They are very pleasant to the taste in a 
fresh state. As the fruit grows near the top of the tree at an altitude of 25 to 50 feet and being 
very large and pulpy, if permitted to ripen and drop to the ground, they burst and are almost 
rendered unfit for use. The Indian mode of collecting them is to take a long light pole, make 
a fork at the top by tying a short piece to it, by which they contrive to bring them within reach. 
Birds and every kind of animal and insect that can reach them are so fond of them that man 
