Cupressus arizonica var. montana

Scientific name: Cupressus arizonica var. montana  (I. Wiggins) e. Little  1966

Synonyms: Callitropsis montana (Wiggins) D.P.Little, Cupressus arizonica subsp. montana (Wiggins) A.E.Murray, Cupressus montana Wiggins, Hesperocyparis montana (Wiggins) Bartel, Neocupressus arizonica var. montana (Wiggins) de Laub.

Common names: San Pedro cypress, San Pedro martír cypress

Description

Tree to 10-20 m tall, with trunk to 1 m in diameter. Bark on trunks becoming fissured, exfoliating slowly in shreddy flakes and strips. Crown dense, conical, broadening with age. Branchlets four-sided, 1.3-2.3 mm in diameter, branching from all four rows of leaves. Scale leaves on branchlets 1-2 mm long, dark green or gray-green with wax, the edges minutely toothed, the back usually with a conspicuous drop of dried resin in an open gland. Pollen cones 2-5 mm long, about 2 mm wide, with (4-)5-8(-10) pairs of pollen scales, each with (three or) four to six pollen sacs, leaves conspicuously and actively glandular. Leaves conspicuously and actively glandular. Seeds red-brown or dark brown, not glaucous. Cotyledons three to five (or six).

Sierra San Pedro Martír, northern Baja California (Mexico); 1,900-2,520 m.

Conservation Status

Red List Category & Criteria: Critically Endangered

The estimated number of mature trees of this variety is fewer than 250, which would place it as Endangered under criterion D. However, the trees are extremely difficult to find and this number is therefore uncertain. Mapping the known occurrences from herbarium specimens is similarly difficult for a lack of fixed toponyms in the area, but most collections were made in a very small area around the summit Cerro de la Encantada. Therefore, the extent of occurrence (EOO) is likely to be much less than 100 km² (here calculated as 46 km² based on four map points of collected specimens) while there is a continuing decline inferred from unrestricted grazing. This places the taxon as Critically Endangered under the B criterion.

There are few mature trees in the area from where it was originally described. Individuals that are present are hard to find amongst the other trees (mostly conifers). Montane coniferous forest or clearings in it, with Abies concolor, Pinus jeffreyi, Pinus lambertiana, Populus tremuloides; on dry slopes or in canyons, sometimes in or near creek beds.

Livestock is a threat to this variety: cattle are allowed to graze indiscriminately throughout the reserve, these cattle are damaging seedlings and preventing them from maturing.

This variety is used as an ornamental tree. The remaining trees are found within a national reserve.

References

• Farjon, A. (2010). A Handbook of the World's Conifers. Koninklijke Brill, Leiden.
• Eckenwalder, J.E. (2009) Conifers of the World: The Complete Reference. Timber Press, Portland.
• IUCN Red List of Threatened Species, International Union for Conservation of Nature and Natural Resources. Cambridge, UK /Gland, Switzerland

Copyright © Aljos Farjon, James E. Eckenwalder, IUCN, Conifers Garden. All rights reserved.