262 APPENDIX. 



Humboldt, with insufficient data before him, placed the lower limit of oaks on the 

 eastern side of Mexico at 2400 feet ; but subsequent explorations prove that they 

 range, in certain districts at least, from the sea-coast up to an altitude of 12,000 feet. 

 Quercus oleoides * descends to the very coast in the State of Vera Cruz, forming small 

 groves on the savanas, rarely forests. It is a handsome though small tree, and is 

 usually covered with showy epiphytical and parasitical plants belonging to the Orchidese, 

 Aroidese, BromeliaceEe, Piperaceae, Loranthacea?, &c. The country rises imperceptibly 

 from the coast, and at 2000 to 3000 feet other species of oak appear, forming small 

 open forests. They are trees of small dimensions, having small, rigid, usually woolly 

 leaves. Quercus petiolaris, Q. tomentosa, and Q. affinis are characteristic of this belt. 

 At an elevation of 3000 feet oak trees are larger and loftier and form dense forests 

 composed of a considerably increased number of species. Here the mean temperature 

 is 62°'5 F., and the rainfall great. The principal species of this region are: — Q.jala- 

 pensis, one of the largest of Mexican oaks ; Q. alamo, a stupendous tree with large 

 coriaceous leaves ; Q. polymorpha, a small species of crooked growth ; Q. lanceolata, 

 with willow-like leaves, and the handsome Q. ghiesbreghtii. They are laden with 

 epiphytical and parasitical plants of the orders named above and others. Beneath the 

 shade of the oaks grow various species of Chamwdorea, and on their roots the scarlet 

 Monotropa coccinea and Conopholis sylvatica. A variety of woody climbers of the 

 genera Banisteria, Paullinia, Serjania, Smilax, Bubus, and Vitis connect the stems 

 and branches and render the forests impenetrable. On the outskirts of the forest an 

 exceedingly elegant and slender bamboo (Arundinaria acuminata) abounds ; its tough, 

 flexible stems rise to a height of twenty-five feet and are no thicker than a goose- 

 quill. 



Above this rich region of plants the gently sloping plains cease, the country becomes 

 mountainous, and at 4000 to 5000 feet palms disappear and are replaced by tree- 

 ferns. The cooler atmosphere, abundant moisture, and broken country offer the most 

 favourable conditions for the oak, and it is here that the species find their greatest 

 concentration in Mexico. Dense forests of numerous species clothe the mountain- 

 sides. In addition to those already named, there are many other species, some of 

 them, like Quercus galeottii and Q. insignis, are remarkable for the very large size of 

 their acorns. Although here as elsewhere in Mexico the oaks are evergreen, they are 

 nearly leafless during a very short period of the year in consequence of the continued 

 violent northerly winds. Many elegant epiphytes, at other seasons inconspicuous, come 

 into flower at this period, and embellish the trees with bright colours. Among them 

 are Juanulloa parasitica, Columnea schiedeana, various species of Echeveria, Orchideee, 

 and Bromeliaceae. At elevations of 6000 to 7000 feet pines begin to mingle with the 

 oaks; yet the latter still predominate and constitute the bulk of the forests. The 

 prevailing species in this region are Quercus lanceolata, Q. laurifolia, and Q. glabrata, 

 * Several of the specific names mentioned in these extracts stand as synonyms in our Enumeration. 



