Ceanothus sonomensis

J. T. Howell

Leafl. W. Bot. 2: 162. 1939.

Common names: Sonoma ceanothus
EndemicConservation concern
Treatment appears in FNA Volume 12. Treatment on page 103. Mentioned on page 78, 95, 102.

Shrubs, 0.5–1 m, often moundlike. Stems erect to ascending, not rooting at nodes; branchlets gray to grayish brown, rigid, strigillose, glabrescent. Leaves not fascicled; petiole 0–1 mm; blade cupped, widely obovate to suborbiculate, 5–12 × 2–10 mm, base cuneate, margins not revolute, wavy, spinose-dentate, teeth 2–4, apex widely notched; abaxial surface pale green or grayish green and glaucous, strigillose on veins, adaxial surface shiny green, glabrous. Inflorescences axillary or terminal, 0.8–1.5 cm. Flowers: sepals, petals, and nectary blue to lavender. Capsules 4–5 mm wide, usually not, sometimes weakly lobed; valves smooth, horns subapical, minute to ± prominent, erect, intermediate ridges absent. 2n = 24.


Phenology: Flowering Mar–Apr.
Habitat: Sandy to rocky soils derived mostly from volcanic substrates, slopes, ridges, chaparral.
Elevation: 100–700 m.

Discussion

Ceanothus sonomensis is distinctive in having spinose-dentate, few-toothed leaves, and slender fruit horns two to three millimeters; it occurs at a few scattered localities in the mountains of Napa and Sonoma counties.

Selected References

None.

Lower Taxa

None.

"thick" is not a number.

... more about "Ceanothus sonomensis"
grayish green +  and pale green +
strigillose +  and glaucous +
perigynous +  and epigynous +
Clifford L. Schmidt† +  and Dieter H. Wilken +
J. T. Howell +
cuneate +
Ceanothus sect. Cerastes +
3-veined +  and veined +
not gland-dotted +
0.5 cm5 mm <br />0.005 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
3[-5]-veined +  and pinnate +
spinulose +, spinose +, serrate +  and entire +
denticulate +, dentate +, crenulate +, crenate +  and serrulate +
widely obovate;suborbiculate +
2mm;10mm +
not thorn-tipped +
glabrescent +  and strigillose +
0.4 cm4 mm <br />0.004 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
Sonoma ceanothus +
100–700 m. +
Sandy to rocky soils derived mostly from volcanic substrates, slopes, ridges, chaparral. +
subapical +
minute +
free +  and adnate +
0 cm0 mm <br />0 m <br /> (0.05 cm0.5 mm <br />5.0e-4 m <br />) +
terminal +  and axillary +
unisexual +  and bisexual +
0.8 cm8 mm <br />0.008 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
deciduous +  and persistent +
blue;lavender +
intrastaminal +
superior +  and inferior +
not fleshy +
perigynous +  and epigynous +
adnate +  and distinct +
6 +  and 5 +
Clawed (?) +, Obovate (?) +  and Spatulate (?) +
0 cm0 mm <br />0 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
Flowering Mar–Apr. +
2-4-carpellate +
Leafl. W. Bot. +
intermediate +
pink +, usually white +  and cream blue or purple +
distinct +
spreading +  and incurved +
6 +  and 5 +
keeled;lanceolate;deltate +
Endemic +  and Conservation concern +
not rooting +
erect +  and ascending +
Ceanothus sonomensis +
Ceanothus subg. Cerastes +
species +
paniclelike +  and racemelike +
not gland-tipped +
unarmed +  and armed +
polygamous +, dioecious +  and synoecious +