PlantcB Lindheimeriancc. 237 



Many plants then bloom a second time ; some, indeed, in this 

 fertile climate, bloom oftener than that, almost after every 

 period of rains. 



" A short distance north of this region, steep and sterile 

 declivities, covered by loose rocks, rise to the first plateau, 

 just mentioned. The high plains which are now reached 

 are mostly sterile and stony, and often large faces of naked 

 rocks are exposed. Many interesting plants mentioned in this 

 catalogue, are peculiar to these plains : the smaller Cactaceae, 

 Echinocactus setispinus, Cereus caespitosus, several Mammil- 

 lariae, and prostrate Opuntiae grow here ; different species of 

 Yucca are common ; the curious and stately Dasylirion is 

 here first met with. The trees of this region are Elms and 

 Cedar among the rocks, and Cedar again, finely developed, 

 along the banks of the streams, where Cercis occidentalis, the 

 shrubby Red Bud, forms thickets. Juglans fruticosa and 

 Morus parvifolia are here found ; the Live Oak dwindles 

 down to a shrub ; and low bushes of Vitis rupestris, the 

 mountain grape, cover large tracts of these plains. 



" Twenty to thirty miles farther northwest the country rises 

 again and becomes more hilly, and regular conic or pyramidal 

 elevations, often showing the horizontal strata of the cretace- 

 ous limestone exposed in naked terraces, rise one behind the 

 other, producing many peculiar plants. The valleys between 

 them are often wide, with a thin soil, covered with grass and 

 often with sparse Post Oaks ; or they are narrower, without 

 any timber, but more fertile. The springs are here numerous 

 and beautifully limpid, of a temperature of about 67 or 68 

 degrees; the streams clear and rapid. The beds of the 

 larger watercourses are often entirely dry in summer, leaving 

 a wide, stony, or pebbly bed or naked rocks, abounding 

 with interesting plants. The banks of the deeper streams are 

 thickly covered with stately Cypress trees. 



" A few miles north of the Pierdenales the first outlier of 

 the granitic formation is seen, which is found extensively 

 developed on the Liano. The vegetation here begins to show 



JOURNAL B. S. N. H. 31 JA.N. 1850. 



