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Abstract: During a survey of the flora of the Mexican state of Durango, a subalpine, shrubby–prostrate form of Juniperus blancoi Martinez was discovered on the summit of Cerro Huehuento. A comparison among populations of J. blancoi growing in different environments indicate that this subalpine taxon is differentiated in its morphology and RAPD DNA banding from J. blancoi populations growing at lower elevations. A new variety is recognized, J. blancoi Mart. var. huehuentensis R. P. Adams, S. González and M. González Elizondo. In addition to being shrubby–prostrate in habit, J. blancoi var. huehuentensis has the female cones attached to the lower sides of planate branchlets. A comparison of the leaf essential oils of Juniperus scopulorum, Juniperus mucronata, J. blancoi and J. blancoi var. huehuentensis revealed that the oil of var. huehuentensis exhibited few differences from typical J. blancoi. [Copyright &y& Elsevier]

The identity of a major unknown component in Juniperus volatile leaf oils has recently been determined as pregeijerene B. The occurrence of pregeijerene B in Juniperus is shown to be highly correlated with 8-α-acetoxyelemol. These compounds are shown to be present in section Sabina, but absent in sections Caryocedrus and Juniperus. In section Sabina, these compounds are very common among the smooth leaf margined, one seeded junipers of the eastern hemisphere and the smooth leaf margined junipers of the western hemisphere. Pregeijerene B and 8-α-acetoxyelemol are thought to arise from 8-α-acetoxyhedycaryol, accounting for their co-occurrence. [Copyright &y& Elsevier]

DNA was examined by RAPD banding for Junipers chinensis, J.c. var. sargentii, J.c. var. tsukusiensis, J. communis, J.c. var. nipponica, J.c. var. saxatilis, J. conferta, J. formosana, J. procumbens, J. rigida, J. taxifolia and J.t. var. lutchuensis. The DNA data readily separated junipers of section Sabina from section Juniperus. J.c. var. tsukusiensis from Taiwan was found to be sufficiently different from J.c. var. tsukusiensis (Yakushima) to warrant the recognition of a new variety: J. chinensis var. taiwanensis R.P. Adams and C-F. Hsieh nov. var. Juniperus formosana from mainland China was found to be different from J. formosana from Taiwan and a new variety is recognized: J. formosana var. mairei (Lemee and Lev.) R.P. Adams and C-F. Hsieh comb. nov. Juniperus communis var. nipponica was found to be very distinct from J. communis and this supports its recognition as a variety. The recognition of J. conferta as a variety of J. rigida [J. rigida var. conferta (Parl.) Patschke] is supported by the data. The data also supports the recognition of J. lutchuensis Koidz. [=J. taxifolia var. lutchuensis (Koldz.) Satake] and J. morrisonicola Hayata [=J. squamata var. morrisonicola (Hayata) H.L. Li and H. Keng] at the specific levels. [Copyright &y& Elsevier]