B. Papp szerk.: Studia Botanica Hungarica 34. 2003 (Budapest, 2003)

Debreczy, Zsolt; Rácz, István: A re-assessment of the new taxa of firs (Abies Mill.) reported from Mexico in 1995

7 median resin canals in the leaves; and soon after, surprisingly, another species with 4 resin canals was located in the similarly mild and humid habitat of a hidden valley in the state of Oaxaca (A. zapotekensis Debreczy, Rácz et Ramirez, see below). The taxonomic value of the number and position of the resin canals is well discussed in the literature (ORR 1937, LIU 1971, etc.). GAUSSEN (1964) thinks that marginal position of the resin canals is a younger character than median, supported by the observation that leaves on sterile shoots usually have marginal resin canals, while fertile ones of the same specimen are typically median (FERRÉ 1941). The phylogenetic importance of the resin canal number is little understood. Except for A. hickelii in Mexico, only two species: A. firma Sieb, et Zucc. of Japan and A. bracteata (D. Don) A. Poit. of Pacific North America were known so far occasionally to have more than two, namely 4, resin canals. We suspect that this is either an ancient, "primitive" character or the consequence of rapid changes in climatic circumstances during the history of the species. In the ancient group of Gymnosperms, Podocarpus (in a broad sense) there are several species with more than two resin canals (e.g., up to 10 in sect. Eupodocarpus such as in P. rostratus Laurent) and their position is typically median. Further study for a better understanding of the systematic position of these newly discovered relict, endemic species, should involve the investigation of questions relating to the number of the resin canals. There were only a few fir species known in Mexico having enclosed bracts: excluding the southernmost types of Abies concolor (Gord. et Glend.) Lindl, ex Hild. known from northern Mexico, together with Abies magnifica A. Murr, in Baja California, only Abies guatemalensis Rehd. (not including A. g. var. tacanensis (Lund.) Mart, and the variety described here (var. longibracteata Debreczy et Rácz)), Abies durangensis Mart., A. d. var. coahuilensis (I. M. Johnst.) Mart, and Abies mexicana Mart. Abies guatemalensis was described by Alfred Rehder in 1939, the others by Maximino Martinez in 1942. More recently, biol. Sergio Zamudio Ruiz (Instituto de Ecologia, C. R. Del Bajio, Patzcuaro, Michoacán) reported (pers. comm.) a species from the state of Querétaro with two resin canals and short, enclosed bracts. Our recent exploration extended this list by three more species having this character: Abies hidalgensis, A. neodurangensis Debreczy, Rácz et Salazar, and A. zapotekensis (see below). Abies guatemalensis, a species with enclosed bracts (Figs 19-20, 31, 34), has an extended population in Guerrero with relatively large cones and exserted bracts described here as A. guatemalensis var. longibracteata (Figs 1, 29-30, 32). So far only a southern form with fine needles, hairy branchlets, and smaller, narrow cones was known to have bracts exceeding the cone scales (var. tacanensis (Lund.)