Two Species of Bryoerythrophyllum (Pottiaceae) New to Mexico

Abstract

Bryoerythrophyllum andersonianum, sp. nov., and B. bolivianum (C. Muell.) Zand. are reported from Cofre de Perote, a volcanic peak in the state of Veracruz, Mexico. The latter species is disjunctive to a narrow range in the Andes of Bolivia and Peru. The montane-alpine regions of the Mexican Volcanic Belt east of Mexico City have been relatively ignored since the collecting activities of Bourgeau, Liebmann, Mueller, Sartorius and Sall6 in the mid-1800's (Bescherelle 1872a,b; Crum 1951; Delgadillo 1969, 1971, 1975). The Cofre de Perote (Nauhcampat6petl) is situated at 1933'N, 97'14'W, and is a conspicuous box-like volcanic plug standing at the eastern edge of the Mexican Central Plateau, just south of the village of Perote and ca. 70 km north of Mount Orizaba (Citlalt6petl). The elevation at the top is 4282 m.s.m., and the plug is composed of andesites of angite and hypersthene. The shoulders and slopes of the Cofre have a surface of erosion products, including boulders, from volcanic material. The slopes are scarred by three lava flows with attendant cones, and by several barrancas (canyons). The original vegetation below the plug was parklike and composed of high-elevation conifers scattered among grasses (for additional description see Zander et al. 1981). This has been disturbed by agriculture, particularly of potato crops. The annual rainfall near the summit approaches 1000 mm, with much of it occurring between July and October. Inferring temperatures from those known at Perote and Jalapa, it appears that the annual mean temperature should be about 2.20C, with a monthly high of 4.4'C in May and a monthly low of 0.60C in December. According to Trewartha (1961), eastern Mexico has wet summers and falls and relatively dry winters and springs, but there is no real dry season such as occurs in western Mexico. Much summer rainfall in the east is of orogeographic origin. Recent bryological study in this area has turned up two species new to science, Philonotis corticata Crum & Griff. (Crum & Griffin 1981) and Morinia saitoana Zand., Delg. & Eckel (Zander et al. 1981). Two additional species from this mountain, one new and the other highly disjunctive in range, are reported here. FIGURES 1-11. Bryoerythrophyllum andersonianum sp. nov. 1. Habit, x9.4. 2-4. Cauline leaves, x18.3. 5. Perichaetial leaf, x18.3. 6. Margin at midleaf, x444. 7. Leaf apex, x444. 8. Transverse section at midleaf, x444. 9. Stem transverse section, x444. 10. Rhizoids bearing propagula, x 444. 11. Papillae of upper laminal margin, x1050. 007-2745/81/543-547$0.65/0 This content downloaded from 157.55.39.220 on Fri, 02 Sep 2016 04:21:49 UTC All use subject to http://about.jstor.org/terms 544 THE BRYOLOGIST [Volume 84