8 INSTITUTE OF SOCIAL ANTHROPOLOGY 
are frequently semicultivated in hedgerows and in 
house lots. Agave (akimba; A. latissima, A. 
americana) is also a frequent hedge plant found 
particularly on the outskirts of settlements, and 
the tree yucca or izote (¢ambasa; Yucca australis), 
although more common at lower altitudes, is often 
seen In Sierra villages. Understory vegetation in 
the oak-pine zone is sparse, possibly owing to the 
annual burning of herbaceous plants in the forest 
to improve summer forage. Some of the more 
prominent understory plauts are  zarzamora 
(¢ttn; Rubus sp.), a wild blackberry especially 
abundant along hedgerows, and wild grape vines 
(Vitis sp.). Various epiphytes, such as orchids 
of many species, are found on the trunks and 
branches of pine and oak throughout the Sierra. 
Although meteorological data are lacking, the 
climate of elevations above 10,000 feet is possibly 
Cwe, i. e., cold winters and cool summers (map 4). 
Such elevations occur on the upper slopes cf the 
higher volcanoes, where snow occasionally falls 
and where fir (Abies religvosa) forms the ,dominant 
vegetation. On slopes above 8,700 feet this tree 
(pinabete, t*ktimbu) starts to appear among pine 
and oak. At 10,000 feet solid stands of fir begin 
and continue to the mountain peaks, where high 
altitude pine (P. hartwegii) has gained a foothold in 
eracks and crevices in rocky cliffs. Understory 
vegetation in the fir forest coasists of various 
herbaceous plants, including a bunchgrass cailed 
zacate or j6éin (Muhlenbergia macroura). The 
green shoots of j6¢in afford the principal forage for 
sheep and goat herds which are grazed on the high 
slopes of Cerro de Patamban and (before the 
eruption of Paricutin) on Cerro de Tancitaro. 
The type of original vegetation in the basin 
plains within the Sierra is problematical. Prob- 
ably cleared and cultivated for more than 300 
years, these plains now show little evidence of 
the original vegetation cover. The dark-colored 
soil of the plains suggests the former presence of 
a grass cover, possibly with scattered oaks and 
pines. 
The Lake district.-According to temperature 
figures, the shores of Lake Patzcuaro fall within 
the tierra fria climate (Cwb). Owing to higher 
winter temperatures than those experienced in 
the Sierra, and to absence of fog, the Lake district 
enjoys a warm phase of Cwh (possibly transitional 
between Cwb and Cwa). Oak and associated 
broadleaf trees, such as madrono, jaboncillo, ete., 
PUBLICATION NO. 7 
form the dominant plant complex of a belt 3 km. 
wide around the lake. Moreover, colorfn 
(pforén¢a; Hrythrina americana), casahuate 
(Ipomoea murucoides), and zapote blanco (uriata; 
Casimiroa edulis), all characteristic of the warmer 
sections of the northern plateau, are common 
hedge plants in the Lake area. Along the lake 
shore, water-loving plants, including a willow 
(tatimu; Salix bonplandiana), shrubs of ““tepozin”’ 
(Buddleia sp.), and clumps of bamboolike carrizo 
(pfatamu; Arundo donar) are not uncommon; 
while in marshy sections canebrakes (tule or 
pa¢imu; Cyperus thrysiflorus) abound. Other 
aguatic plants include various waterlilies and 
hyacmths (Nymphaea sp.; ichhornia speciosa). 
Possibly a mixed pine-oak forest once covered the 
lower slopes bordering the lake, but, if so, the pines 
have long since been destroyed for firewood and 
lumber. Occasionally lone specimens of Pinus 
leiophylla are found on the outskirts of lake 
villages. 
The northern plateau.—The Cwbh climate ex- 
tends northward from the Sierra into the south- 
eastern part of the northern plateau area. In the 
middle and lower Rio Lerma Basin (Bajio) and in 
La Canada, however, the Cwa climate of the 
tierra templada occurs. In both Cwa and Cwhbh 
areas of the northern plateau, oak and pine forests 
occupy only the summits of the higher hills, below 
which exist stands of oak and madrofo. The 
lower slopes and plains carry an association of 
grass and shrub, the latter consisting of casahuate, 
zapote blanco, tejocote, palo blanco (Lysiloma 
candida), granjeno (Celtis pallida), jara amarillo 
(téksten; Senecio salignus), all typical of the more 
humid portions of the central plateau. Xerophy- 
tes, such as huisache (Acacia sp.), mesquite 
(Prosopis juliflora), and various cacti (mainly 
Opuntieae), are common. In the plains, fresnos 
(padimu; Fraxinus sp.) form gallery forests along 
streams, and in draws within the hills hydrophy- 
tes, such as wild ahuacate and other laurels, pre- 
dominate. Formerly extensive meadows existed 
at the edge of swamps and lakes, particularly in 
the lowlands east of Lake Chapala and the well- 
watered plains near the northern edge of the 
Sierra. In the northern plateau pine and oak 
forests were formerly more extensive than at 
present. Many of the hilltops north of the 
present México-Guadalajara highway, which are 
now barren cf arboreal vegetation, were once 
