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Slender-horned Spineflower Back to Plant Page
Dodecahema leptoceras

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About Slender-horned Spineflower (Dodecahema leptoceras) Dodecahema is a genus of plants in the family Polygonaceae with a single species restricted to California, where it is an endangered species on the state and federal levels. Its common name is slender-horned spineflower. This is a small annual plant forming a patch of spreading basal leaves a few centimeters in diameter, or slightly larger when more moisture is available. It bolts an erect stalk upon which it bears inflorescences of flowers. Each group of white or pink flowers is enclosed in a tiny cup of fused bracts which is only a few millimeters wide. The fruit is a dark achene about 2 millimeters long. This plant grows in the silt-rich floodplains and washes of the foothills of the Transverse Ranges and the Peninsular Ranges of southern California. It is known from fewer than 40 reported sightings, many of which were in locations that have since been claimed for development or otherwise altered. About 19 occurrences are believed to exist now. This plant has been recorded in only a few general areas, including Tujunga Wash and the floodlands surrounding the Santa Ana and San Jacinto Rivers. The main threats to this species include water diversion, off-road vehicles, invasive species of plants, and development on the private property where most occurrences of this plant are located.
Plant Description
Plant Type
Annual herb

Max. Height
1.2 - 4 in (3 - 10.2 cm)

Flower Color
Pink, White

Native Status
Natural Setting
Elevation ?
284' - 5871'

Annual Precip. ?
3.5" - 34.8"

Summer Precip. ?
0.25" - 1.55"

Coldest Month ?
44.7° F - 61.4° F

Hottest Month ?
64.5° F - 88.8° F

Humidity ?
2.18 vpd - 42.81 vpd

Landscaping Information
Nursery Availability
Never or Almost Never Available

Other Names
Common Names
Slenderhorn Spineflower

Sources include: Wikipedia. All text shown in the "About" section of these pages is available under the Creative Commons Attribution-ShareAlike License. Plant observation data provided by the participants of the California Consortia of Herbaria, Sunset information provided by Jepson Flora Project. Propogation from seed information provided by the Santa Barbara Botanical Garden from "Seed Propagation of Native California Plants" by Dara E. Emery. Sources of plant photos include CalPhotos, Wikimedia Commons, and independent plant photographers who have agreed to share their images with Calscape. Other general sources of information include Calflora, CNPS Manual of Vegetation Online, Jepson Flora Project, Las Pilitas, Theodore Payne, Tree of Life, The Xerces Society, and information provided by CNPS volunteer editors, with special thanks to Don Rideout. Climate data used in creation of plant range maps is from PRISM Climate Group, Oregon State University, using 30 year (1981-2010) annual "normals" at an 800 meter spatial resolution.

Links:   Jepson eFlora Taxon Page  CalPhotos  Wikipedia  Calflora

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