Arctostaphylos otayensis
| Arctostaphylos otayensis | |
|---|---|
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Scientific classification 
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| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Asterids |
| Order: | Ericales |
| Family: | Ericaceae |
| Genus: | Arctostaphylos |
| Species: | A. otayensis
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| Binomial name | |
| Arctostaphylos otayensis | |
Arctostaphylos otayensis is a species of manzanita commonly known as the Otay manzanita. It is a rare perennial shrub native to the mountains of southwestern San Diego County, California and northwestern Baja California, where it grows in chaparral habitats on metavolcanic soils, mostly in the San Ysidro Mountains. The white urn-shaped flowers bloom from winter to spring. Because of the small range of this species and a number of threats, it is of conservation concern.
Description
Arctostaphylos otayensis is an erect or mound-forming shrub, 1–3 m (3.3–9.8 ft) tall. It lacks a burl, and has twigs that are sparsely covered in short hairs and long glandular hairs. The leaves are erect, borne on petioles 5–8 mm (0.20–0.31 in) long. The base of the leaf near the petiole has a rounded or truncate shape. The leaves have a gray-glaucous color and are narrowly elliptic or oblong-elliptic to ovate in shape, measuring 2–3 cm (0.79–1.18 in) long by 1–2 cm (0.39–0.79 in) wide.[2]
The inflorescence is a panicle with 4 to 7 branches. The young inflorescence branches have an erect or ascending orientation, and are covered in hairs like those on the twigs. The inflorescence is covered in leaflike bracts. The flowers are attached to pedicels 3–8 mm (0.12–0.31 in) long. The flowers are white, with a conic to urceolate shape, and with an ovary covered in dense white hairs. Flowering is from winter to early spring. The fruits are globose in shape, mostly lacking hairs, and are 6–8 mm (0.24–0.31 in) in diameter.[2]
Taxonomy
Arctostaphylos otayensis was described in 1939 by botanists Albert E. Wieslander and Beryl O. Schreiber in Madroño. The type specimen was collected by H. A. Jensen on Otay Mountain on November 3, 1937, with the specific epithet derived from the type locality. Wieslander and Schreiber noted that A. otayensis resembled A. glandulosa in many respects, but differed in its lack of a burl and characteristically small and pale brown fruits.[3]
Distribution and habitat
Arctostaphylos otayensis is mostly restricted to the San Ysidro Mountains of San Diego County, California and Tijuana Municipality, Baja California. Smaller populations occur on neighboring San Miguel Mountain to the north,[4] and to the south near La Misión.[5]
A. otayensis is found in chaparral and cismontane woodland habitats in metavolcanic soils, where it occurs on rocky slopes or outcrops.[4] Associates in chaparral include Adenostoma fasciculatum, Arctostaphylos glandulosa, Malosma laurina, Ceanothus, and Chamaebatia australis. In Tecate cypress associations, it occurs with Xylococcus bicolor, A. glandulosa, Cercocarpus betuloides, Comarostaphylis diversifolia, and C. australis.[3] The San Ysidro Mountains are an ancient volcanic system which supports a high number of endemic taxa like A. otayensis possibly limited to the metavolcanic rocks and soils. As this species lacks a burl, it cannot resprout after intense fires.[4]
Conservation
Arctostaphylos otayensis is ranked as a G1 Critically Imperiled species by NatureServe because of its small distribution, threats, and declining number of occurrences. Out of the 18 known occurrences of A. otayensis in San Diego County, 15 are historic and may also be extirpated. Threats include development, roads, trampling, and improper fire regimes.[1] The San Diego Zoo Wildlife Alliance and California Botanic Garden work to conserve this species.[4]
References
- ^ a b NatureServe (January 30, 2026). "Arctostaphylos otayensis". NatureServe Explorer. Arlington, Virginia. Retrieved February 25, 2026.
- ^ a b Parker, V. Thomas; Vasey, Michael C.; Keeley, Jon E. "Arctostaphylos otayensis". In Flora of North America Editorial Committee (ed.). Flora of North America North of Mexico (FNA). New York and Oxford: Oxford University Press – via eFloras.org, Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
- ^ a b Wieslander, A. E.; Schreiber, Beryl O. (January 1939). "Notes on the Genus Arctostaphylos". Madroño. 5 (1). Lancaster, Pennsylvania: California Botanical Society: 38–47 – via Biodiversity Heritage Library.
- ^ a b c d "Otay Manzanita". Center For Plant Conservation.
- ^ Rebman, Jon P.; Gibson, Judy; Rich, Karen (15 November 2016). "Annotated Checklist of the Vascular Plants of Baja California, Mexico" (PDF). Proceedings of the San Diego Society of Natural History. 45. San Diego Natural History Museum: 138 – via San Diego Plant Atlas.
External links
Media related to Arctostaphylos otayensis at Wikimedia Commons
Data related to Arctostaphylos otayensis at Wikispecies- Jepson Manual Treatment
- USDA Plants Profile
- Photo gallery
