18 UNITED STATES AND MEXICAN BOUNDARY. 
when green. In this locality are also found the beautiful Ceanothus rigidus, Pitavia dumosa, 
Adenostoma fasciculata, and a species of scrub oak, all forming dense thickets. 
We must not omit to mention the Cactacew, which here present species of all the extra 
tropical genera, as remarked by Dr. Engelmann in his memoir upon this family. "These plants, 
from their striking and singular forms, impart a characteristic feature to the region they inhabit. 
А new species of pine is peculiar to the district now under consideration. It occupies an arid 
tract near the ocean beach, about twelve miles north of San Diego, at the entrance to Solidad 
valley. In this locality (the only one in which it has been found) it forms a small sized tree, 
with rather open foliage. It is particularly distinguished by its long fascicles of leaves, which 
are in fives, and its large ponderous cones. This species, the specific characters of which will be 
found more fully described in the following list, I have ventured to designate, in compliment to 
a distinguished American botanist, as Pinus Torreyana. 
Along the borders of the streams which traverse this Supra-Littoral district are found the 
common cotton-wood, (Populus angustata,) the Platanus Mexicanus, and, in the lower portion of 
the San Luis Rey valley, an Alnus; these, with various species of willow, make up the proper 
timber growth of this region. The undergrowth in these localities consists mainly of coarse 
representatives of the order Composite, conspicuous among which are several shrubby species of 
Baccharis. In moist places Anemiopsis Californica is frequently met with, and where the soil is 
rich the surface is covered by a rank growth of wild mustard (Sinapis nigra) and mallows, 
(Malva obtusa.) 
The herbaceous and annual plants of this region are so numerous that we can only allude to 
a few of the more striking and characteristic. 
It is in the latter part of winter and during the earlier spring months that California puts on 
her richest floral garb. Then the arid hills assume an aspect far different from their desert-like 
summer appearance. In February the moistened ground becomes arrayed in an assemblage of 
varied tints. The pale blossom of the elegant Dodecatheon integrifolium nod on every hill side, 
blue Lupines and rainbow colored Gilias deck the ground, and various ferns and mosses appear. 
The Ribes speciosum hangs its scarlet pendants, and the rich yellow flowers of Viola pedunculata 
are abundant everywhere. Even the numerous northern genus Saxifraga is represented here 
by more than one species. A large number of Hydrophyllacee, including species of Nemophila, 
Phacelia, and Eutoca, are among the early tokens of spring, while the orange colored flowers of 
Escholizia, the pale blooms of Platystemon, and the pink ones of Meconopsis, show that the 
poppy family contribute largely to make up the vernal flora. Among the twiners are a species 
of Clematis that is either new or a variety of C. pauciflora and Megarrhiza Californica of Torrey ; 
the latter plant, which hangs its prickly burs from almost every bush, is remarkable for the 
enormous size of its root. Further to the north the valleys are clothed with a luxuriant growth 
of wild oats, (Avena fatua,) which is во extensively naturalized that it gives to every fertile 
tract the appearance of a cultivated field. The wide plains that border the sea in the neigh- 
borhood of Los Angeles .are covered with the richest pasturage. The Erodium cicutarium, 
(called here “pin grass,” and furnishing a highly esteemed fodder,) with several species of wild 
clover, (Trifolium and Medicago,) are mingled with a variety of other herbage, and thus serve to 
give a meadow-like aspect to this teeming land. Such is the general appearance of the country 
from February to April, inclusive, and then is to be seen the glory of the Californian flora. 
