Hesperocyparis revealiana

(Silba) Silba 2009

Common names

El Rincon cypress.

Taxonomic notes

Synonymy: see POWO (accessed 2023.12.16). Type, Mexico: Baja California: Sierra Juarez: El Rincon de Santa Catarina, 1200 m elevation, 1974.04.21, Moran 21251 (Silba 1981).

Evidence from leaf essential oils and DNA sequences indicates that this taxon is closely related to but distinct from Hesperocyparis montana (Adams et al. 2014). The analysis using chloroplast DNA found H. revealiana sister to H. montana in a clade sister to H. arizonica+forbesii+glabra+guadalupensis+stephensonii, while the leaf essential oil analysis indicated distinct compositions for the two species, with no evidence for hybridization. On this basis it is sufficiently distinct from other Hesperocyparis in the California-Arizona-Mexico region to warrant treatment as a distinct species.

Description

Trees to 20 m tall. Crown dense, bushy. Bark smooth, brownish-red, soon exfoliating in short strips. Foliage gray-green, scale-like, 1-1.5 mm long, glands apparent. Pollen cones 3-4 × 1.8 mm with 8-12 scales. First-year cones glaucous. Mature cones serotinous, glaucous brown, pendant in small clusters of 1-3 cones on peduncles longer than the cone diameter, 15-20 mm diameter with prominent umbos, composed of 6-10 scales. Seeds brown, often glaucous. Cotyledons 3-6, 9-10 mm long (Silba 1981, Bisbee and Maerki 2012a).

In most respects this species resembles Hesperocyparis stephensonii. Some of the most conspicuous differences from that species include:

• Crown form is open and irregular on H. stephensonii, but dense and roughly pyramidal on H. revealiana.
• Foliage is dark green on H. stephensonii, but paler green and usually glaucous on H. revealiana.
• Bark is gray with peeling reddish scales on H. stephensonii, but brick-red with peeling red scales on H. revealiana.
• Bark on saplings (ca. 2-3 cm diameter) is olive-green on H. stephensonii, but dark gray on H. revealiana.
• Branching pattern on ultimate shoots is one order higher on H. stephensonii, with smallest branchlets only a few leaves long.

See Bisbee and Maerki (2012a, 2012b) for a very detailed comparison of the two species.

Distribution and Ecology

The type locality is the Rincon de Santa Catarina in the Sierra Juarez of Baja California, and all collections have been from near this location, which is at about 31.65°N, 115.8°W. The type location is at 1200 m elevation (Silba 1981). Much of the population is riparian along intermittent streams, and Malone (2016) reports that seed dispersal is primarily by flowing water. Soils are derived from weathered granitic rocks, and associated species include Quercus peninsularis, Artemisia sp., and bunchgrasses (Malone 2016).

The species has not yet been recognized by the IUCN and thus has no designated conservation status. Per IUCN criteria, it would likely be assessed as "Critically Endangered" due to small size and extent of the known population, and the lack of formal protection.

Remarkable Specimens

No data as of 2023.12.16.

Ethnobotany

No data as of 2023.12.16.

Observations

See Malone (2016) for a detailed, well-illustrated account of how to locate this species in habitat.

Remarks

The epithet revealiana honors James L. Reveal (1941-2015), noted botanist and plant taxonomist.

Citations

Adams, R. P., J. A. Bartel, R. Terry, F. Callahan, and J. Bisbee. 2014. Taxonomy of Hesperocyparis montana, H. revealiana and H. stephensonii: Evidence from leaf essential oils analyses and DNA sequences. Phytologia 96(2):71-83.

Bisbee, J. and D. Maerki. 2012a. Cupressus revealiana (Silba) Bisbee, comb. nova validation as a new Cupressus species. Bulletin of the Cupressus Conservation Project 1(1):3-15. Available: www.cupressus.net/bulletin/bulletin01/BullCCP01_1.pdf, accessed 2012.10.30.

Bisbee, J. and D. Maerki. 2012b. Addendum: Cupressus revealiana (Silba) Bisbee, comb. nova validation as a new species. Bulletin of the Cupressus Conservation Project 1(2):46-47. Available: www.cupressus.net/bulletin/bulletin02/CUrevealianaBisbee2012b, accessed 2019.05.20.

Malone, J. 2016. Cupressus revealiana El Rincon, Sierra Juarez, Baja CA: trip report. Bulletin of the Cupressus Conservation Project 7(2):57-69.

Silba, J. 1981. Revised generic concepts of Cupressus L. (Cupressaceae). Phytologia 49(4):393.

See also

Reveal, James L. 1992. Gentle Conquest: The Botanical Discovery of North America. Washington, DC: Starwood.
Not particularly conifer oriented, but this, Reveal's main foray into popular literature, is a good read, if you're interested in the history of pioneer botanists in New America.