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Hesperocyparis babaddoagae Maerki [TSAR]*

Babad Do'ag western-cypress

Synonyms
  • Cupressus babaddoagae Maerki
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Introduction

The Babad Do’ag western-cypress is an evergreen tree from the Santa Catalina Mountains of southern Arizona, centered on Mount Lemmon (Babad Do’ag). Tree TSAR provisionally recognizes it as Hesperocyparis babaddoagae Maerki [TSAR]* in the Arizonica Clade. The underlying name Cupressus babaddoagae Maerki was formally published in 2025; the Hesperocyparis combination used here is a provisional Tree TSAR combination and is not presented as a formally published ICN name (Maerki 2025).

The lineage is distinguished from sampled H. arizonica by a coordinated suite of characters rather than a single conspicuous trait. Its foliage is strongly whitish-glaucous, immature cones are waxy, cones average fewer scales with smaller mucrones and more irregular scale margins, and seed production per cone and per scale is higher in the published comparison. Seedlings commonly have three or four cotyledons. Importantly, several features persisted in common cultivation, weakening the hypothesis that the entire syndrome is simply a local plastic response to Mount Lemmon conditions (Maerki 2025).

Tree TSAR retains species rank provisionally because the evidence is multidimensional but the population sampling remains narrow. The lineage was not sampled by Li et al. (2026), and no modern population-genomic comparison yet tests Mount Lemmon against broad samples of H. arizonica, H. glabra, and Mexican Arizonica-clade species.

Horticultural and Agricultural Uses

The taxon is known horticulturally chiefly through the cultivated descendants used in its description and comparison. Those plants are scientifically important because they show that the whitish foliage and aspects of crown and cone morphology can persist away from the native site. At present, the taxon is better suited to documented research and conservation collections than to ordinary nursery distribution.

Any propagation should preserve source-tree identity. The protologue includes many measurements from cones and seeds, but the number of genetically independent source trees is much smaller; conflating numerous offspring from the same parent with population-level replication would reduce the value of cultivated material for future taxonomic testing.

Conservation Concerns

No independent modern global conservation assessment was located for H. babaddoagae under either the Tree TSAR combination or the 2025 Cupressus name. Its known distribution is geographically restricted, so even before a formal assessment the lineage warrants careful monitoring and provenance-aware conservation.

The most important immediate conservation need is better information. Population-level genomic sampling across Mount Lemmon and the Santa Catalina Mountains should be paired with broad sampling of H. arizonica, H. glabra, and related Mexican lineages. That work would simultaneously test taxonomic independence, estimate genetic diversity, and identify whether the currently known population represents the full distribution. Until such sampling is available, conservation action should avoid assuming either that the lineage is merely ordinary H. arizonica or that its present known range is complete.

Additional Information

References and Further Reading

Adams RP, Bartel JA, Price RA (2009) A new genus, Hesperocyparis, for the cypresses of the western hemisphere (Cupressaceae). Phytologia 91(1): 160–185. https://www.biodiversitylibrary.org/part/220373.

Li J, Jia S, Wu D, Tao W, Ruhsam M, Mao K (2026) Phylogenomics reveals the reticulate evolution and biogeographic history of New World cypresses, Hesperocyparis (Cupressaceae). Cladistics 42(2): 109–127. https://doi.org/10.1111/cla.70021.

Maerki D (2025) Cupressus babaddoagae, a new cypress species from Arizona. Bulletin of the Cupressus Conservation Project 14(3): 75–114. https://www.cupressus.net/bulletin/31/BullCCP14_3_31.pdf.