f 
[26] . 12 
lizenus collected thg living plant and flowers, and Dr. Gregg the ripe 
fruit. It is distinct fm the other Hehinocacti found in those regions by 
the membranaceous verysthin sepaloid scales on the tube of the flower 
and the juicy glabrous fruit, in which respect it resembles my EH. setispi- 
nus from Texas; 4. terensis, Hpfr., has a juicy fruit, covered with woolly 
and spiny scales; £. Wislizeni and others have a dry fruit, covered with 
hard scales. 
My Opuntia frutescens (Plant. Lindh. |. c. p. 245) which had been col- 
lected by Mr. Lindheimer along the Colorado and Guadaloupe rivers, in 
Texas, was also found south of Chihuahua by Dr. Wislizenus, and again 
along the route near Parras, and below Monterey. The suggestion made 
in the Plant. Lindh., that it may be a southern variety of O. fragilis of 
the Upper Missouri, has proved to be erroneous, as they belong to quite 
distinct sections of the genus Opuntia; O. frutescens, together with O, 
vaginata, (vide note 18,) is one of the Opuntiae cylindraceae graciliores, — 
and is apparently nearly related to O. leptocaulis DC., but is easily dis- 
tinguished by its strong, white, single spines, while O. lept. has 3 short 
blackish bristles. 
Agave Americana, with several relatives, was found in abundance on 
this part of the route; Argemone Mezicana, white, yellow, or rosecolored, 
was frequently met with; Samolus ebracteaius occurred in moist places 
so far inland, and on such elevations, while before it was only known as 
a litoral plant; Malvaceae, Oenotherae, Asclepiadaceae, Giline, Solaneae, 
Justiciae, shrubby Labiatae, were collected of many different species ; but 
the great characteristic of the country were the shrubs forming the often 
impenetrable thickets, called “chaparrdls.”” They are mostly spinous, 
before me 4 inches in diameter, 3 inches in height; the large recurved 
Spines, especially the stoutest central one, which is of a blnish horncolor, 
a int, and iseurved and bent downward like a large fang, 
cover the whole surface of the plant, and give it a very pretty appearance. 
wer radiating spines 6 to 10, upper 12 to 15 lines long; upper central 
spines 12 to 18 lines long, but lower stouter one only 10 to 12 lines in 
length. Flowers described from the shrivelled specimens found on the 
living plant; about 1 inch in length, and probably pale red. I have little 
doubt that some fruits collected in the same region (about San Lorenzo) 
ad been packed up for eight or ten months, mostly do very well now. 
’ sonte te have cerniliaad ool 
* 
