ee er ee ere ey eer ey se es nn ee 
FROM MISSOURI TO SANTA FE AND NORTHERN MEXICO. 57 
scales on the tube of the flower and the juicy glabrous fruit, in which respect it resembles my 
E. setispinus from Texas. #. Texensis, Hpfr., has a juicy fruit, covered with woolly and spiny scales ; 
E. Wislizeni and others have a dry fruit, covered with hard scales. 
My Opuntia frutescens (Plant. Lindh., 1 ¢. p. 245), which had been collected 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. 0. frutescens, 
together with O. vaginata (vide note 18), is one of the Opuntia cylindracee graciliores, and is 
apparently nearly related to O. leptocaulis DC., but is easily distinguished by its strong, white, single 
spines, while 0. dept. has three short blackish bristles. 
Agave Americana, with several relatives, was found in abundance on this part of the route. 
Argemone Mexicana, white, yellow, or rose-colored, was frequently met with; Samolus ebracteatus 
occurred in moist places so far inland and on such elevations, while before it was only known as a 
littoral plant; Malvacee, Gnotheree, Asclepiadacee, Gilie, Solaneee, Justicie, shrubby Labiate, were 
collected of many different species. But the great characteristic of the country were the shrubs 
forming the often impenetrable thickets called “chaparrals.” They are mostly spin 
very much branched, often with remarkably small leaves, and not rarely with edible [113 (29)] 
fruits. Among them many rhamnaceous and celastraceous shrubs, and some Huphor- 
biacee, were particularly conspicuous ; as well as some Mimose@, one of which I must not forget to 
_ mention, because it is perhaps the smallest shrub in this family, not more than one or two inches 
high, with diminutive leaflets, but large purple flowers. It was collected near Chihuahua. 
One of the most offensive of these chaparral-shrubs was the Keberlinia, Zuce., called here 
Junco (Gregg) ; a small tree rather than a shrub, about 10 feet high, stem 4 to 6 inches in diameter ; 
wood hard, dark brown with white alburnum; terminal branches green, with a dark brown spinous 
termination, 1 to 2 inches long, and 14 to 2 lines in diameter; very small subulate leaves soon 
deciduous; small white flowers in short lateral racemes; fruit not seen; in flowerin May. It was 
frequently seen from south of Chihuahua to Monterey (and Matamoros, Gregg). 
We find here again the interesting Chilopsis mentioned above (see note 11), also Larrea gluti- 
nosa (note 10), and another zygophyllaceous shrub, a true Guajacum, which appears to be an 
undescribed species ; it belongs to those plants that connect the Mexican with the Texan flora, as we 
find it extending from Parras to Monterey, and from there to the Upper Colorado, in Texas. Tecoma 
stans reappeared here with smaller pubescent leaves and more alate petiole, though probably not dis- 
tinct from the larger and smoother plant found below Paso. 
The beautiful Fougquiera splendens (see note 16), with its panicles of long tubular crimson - 
flowers, rose here above all other shrubs ; in some instances it reached a height of from 20 to 30 feet, 
and perhaps more, always in single stems. 
A few species of Yucca, together with Opuntia arborescens (note 5), formed almost the only trees 
on the arid plains. But in the valley of the Nazas occur stately trees of a species of Algarobia, dis- 
tinct from the _A. glandulosa of the north, with broader legumes, larger seeds, and few or no glands 
on the leaves. 
* GUAJACUM ANGUSTIFOLIUM, n. sp.: foliis sub-5 (4-8) jugis glaberrimis, foliolis era aeoagees reticulatis ; 
Pedicellis et basi calycis pubescentibus; ovario bilobo, pubescente; capsula bivalvi, seminibus 2 ov 
About Parras; collected also by Dr. Gregg, who has found the plant common from Monclova . tulle Monterey, 
and Camargo ; found by Mr. Lindheimer on the Pierdenales river in Texas; flowers in April and May. Shrub or 
small tree with very knotty branches; leaflets mostly in 5 or 6 pairs, only on young vigorous shoots 6 to 8 pairs, 
mostly a 4 fame long, $ to 1 line wads, reticulated on both sides. Purple flowers 6 lines in diameter; seeds yellow, 
of mall beans. The hard and heavy yellowish brown wood is called “ Guajacan” about Saltillo, and used 
asa solic was in venereal diseases (Dr. Gregg). 
8 
