40 UNITED STATES AND MEXICAN BOUNDARY. 
Subgen. 2. Evczrevs.* 
19. C. Emoryt, E. in Sill. Journ.: caule cylindrico 2-3-pedali prostrato ; ramis adscenden- 
tibus seu erectis; costis 15 tuberculatis; sinubus acute incisis ; areolis confertis orbiculatis, 
junioribus fusco-tomentosis ; aculeis rectis rigidis gracilibus aciculatis e virescenti flavis nume- 
rosissimis intertextis, exterioribus 40-50 tenuissimis stellatim porrectis, centrali singulo robus- 
tiore multo longiore; floribus subterminalibus flavis; tubo breviusculo aculeolato ; bacca globosa 
aculeatissima ; seminibus magnis obovatis acute carinatis basi acutis lucidis minutissime sub 
lente tuberculatis, hilo ventrali angusto; cotyledonibus foliaceis hamatis incumbentibus. 
(Tab. LX, fig. 1-4.) 
On dry hills and mountains, near the coast of California, about San Diégo, growing in thick 
masses, and covering patches of 10 or 20 feet square, Dr. Parry; not north of the boundary 
line, Dr. Le Conte.—Prostrate stems 2-3 feet long ; branches 6-9 inches high, 14 inch in 
diameter ; flowers abundant near the top of the branches, rather short, yellow, 2 or 23 inches 
wide. Fruit 14 inch in diameter, densely covered with numerous pulvilli, each bearing 20 or 
25 stiff yellow spines, from 2 to 6 lines in length, 3 of them stouter and longer than the rest, 
often about an inch in length ; some indistinct remains of the dead flower are hidden amon g the 
spines. Seed 1.2-1.4 line long, with a very prominent keel and linear hilum. The short 
aculeolate flower, persistent on the spinose fruit flower, would seem to refer our plant to 
Echinocereus, but the seed and embryo permit no doubt about its position. I have seen speci- 
mens of a fruit of a columnar Cereus from the Pacific coast near Mazatlan, sent by the late Dr. 
J. Gregg, which is a gigantic representative of our California fruit, and suggests the idea that 
on the western coast of our continent several species exist of a still unknown section of 
Cereus.—This plant, peculiar to the western termination of our boundary line, fitly bears the 
name of the energetic and distinguished commissioner under whose auspices the greater part of 
the interesting plants here described have been collected. 
20. C. varraBiLis, Pfeiff., a tall species, 3-10 feet high, is common to the east as well as west 
coast of tropical Ameriea, extending northward to the mouth of the Rio Grande, and up that 
stream towards Matamoras. Full-grown stems 3-4 angled, with few and stout spines ; but 
young shoots with 8 ribs and numerous slender spines; flowers white, nocturnal ; fruit dial 
about 3 inches long, spinose, crimson externally and internally; seeds obliquely obovate, woe 
pressed, smooth, and shining, 1.5-1.7 line long; hilum subventral, narrowly oblong, linear 
albumen almost none; embryo much curved ; cotyledons large, foliaceous, incumbent. (Tab. 
LX, fig. 5-6.) 
21. C. Gaxaen, E. in Wisl. Rep.: e radice crassa napiformi erectus, gracilis, 2-3-pedalis ; 
ramis paucis erectis 3-6-angulatis atro-virentibus sepe rufescentibus; costis acutis; sulcis 
latis planiusculis ; areolis oblongo-li i : et a ees ‘ 
Pp ; go-linearibus confertis seu subconfertis, junioribus lana e cinereo 
*® This section is proposed here only as a receptacle for our few Cerei not included i 
3 : ed in the other subgenera. It i i i- 
ble that the greater part of the species of this genus will have to be referred here, but it is more tr that a sidin . ere 
tion of the flower and fruit of the numerous southern Cerci will necessitat p= npr 
of the flower usually at length deciduous; seeds mostly smooth and shining, and the embryo hooked, with curved folia- 
