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and from thence to the Upper Colorado, in Texas. Zecoma Stans 
re-appeared here with smaller pubescent leaves and more alate 
petiole, through probably not distinct from the larger and 
smoother plant found below Paso. 
The beautiful Fouguiera splendens, with its panicles of long 
tubular crimson flowers, rose here above all other shrubs ; in 
some instances it reached a height of from twenty to thirty feet, 
and perhaps more, always in single stems. 
A few species of Yucca, together with Opuntia arborescens, 
formed almost the only trees on the arid plains. But in the 
valley of the Nazas occur stately trees of a species of Algarobva, 
distinct from the 4. glandulosa of the north, with broader 
legumes, larger seeds, and few or no glands on the leaves. 
About Saltillo Hehingcactus Texensis, Uptr., (2. Lindheimert, 
Engelm., in Plant. Lindh. |. c.,) was found, which extends from 
here to Matamoros, and to the Guadaloupe and Colorado, in 
‘Texas. The pretty Mammillaria strobiliformis grows on rocks 
near Rinconada. Hunnemannia fumariefolia, Sweet, was col- 
lected near Saltillo, with smaller flowers, (an inch and a half in 
diameter,) and near Rinconada, with larger ones, (three inches 
in diameter) ; an interesting plant, the eastern representative of 
the Californian Aschscholtzia, but perennial, with a small torus, 
a different stigma, &ec. 
I cannot omit introducing here a beautiful shrub discovered 
on the rocks about Agua Nueva and Buena Vista by Dr. Gregg. 
Depending upon Don’s characters of Cowania as correct, I must 
consider this plant as the type of a new genus, which I have 
great pleasure to dedicate to its indefatigable discoverer, my 
friend Dr. Josiah Gregg, whose name has already been frequently 
mentioned in these pages. Greggia rupestris is a lovely, sweet- 
scented shrub, with flowers resembling roses in shape and colour, 
so that Dr. Gregg was induced to name it the “ Cliff rose.” 
North and north-east of Monterey we reach the lower country, 
and with it a different vegetation; here is the home of the 
shrubby Cassiee (Parkinsonia, Casparea, &c.,) aud Mimosee ; 
Sophora, Diospyros, some species of Rhus and Rhamnus are 
common here, as well as a climbing yellow-flowered Hirea, 
while another erect, red-flowered species grows on the table- 
lands near Parras. One of the most beautiful shrubs of that 
district is Leucophyllum Texanum, Benth., with its whitish, to- 
mentose leaves, and sweet-scented blue flowers. It is common 
from San Antonio, in Texas, to Monclova, and from Cerralbo to 
Camargo, but it is not seen on the table-lands. 
Vitis bipinnata and V. incisa, well known in the south-western 
