The Genus Juniperus (cupressaceae) in Mexico and Guatemala: Umerical and Morphological Analysts

The genus Juniperus (Cupressaceae) consists of approximately GO species distributed in the orthern Hemisphere, except for J.yrocera Hocll. which extends into the Southern Hemisphere in Africa (Florin, 1963). The delimitation of the species of Juniperus is difficult in all of the world; few taxonomic studies have encompassed any large geographical or natural province. Gaussen (1968) lists 99 species in the most recent treatmen t of the junipers of the world; however, this is an inflated number since many of the _pecies he recognizes had been reduced to synonymy by earlier authors. Juniperus has been divided into. three sections: Caryocedrus, Oxyeedrus, and Sahina (Endlicher, 1847; Gaussen, 1968). Caryocedrus, a monorypic section, is restricted to the eastern Mediterranean basin; the other two section are dis­ tributed throughout the Northern Hemisphere. Section Oxycedrus is l'epresented in 1 orth America by the circumboreal species J. communis L. The other junipers (approximately 22 species) in orth America belong tOI the section Sabina, which is characterized by opposite or ternate, scale-like adulr leaves, peltate scales in male cones, and female cones terminal on fertile twigs (peduncles). Engelmann (1877) made the first study of the North American (mostly United States) junipers. The genus Juniperus has received considerable attention from North Ame­ rican taxonomists in the past 35 years. Fassett's (1944a, 1944b, 1945a, 1945b, 194.50) and Hall's (1952a, 1952b, 1955, 1962, 1964, 1968) series for mo·rpho­ logical studies concerning hybridization in several species of Juniperus renewed interest in this genus. More recent studies have used more sophisticated tech­ niques for data collection and analysis. Vasek (1966) and Vasek and Scora (1967) examined three wesrern American species morphologically and chemi­ cally. Van Haverbeke (1968), Flake, von Rudloff and Turner (1969, 1973), Adams and Turner (1970), Sehurtz (1971), Adams (1969, 1970, 1972, 1973,