Ceanothus pumilus

Greene

Erythea 1: 149. 1893.

Common names: Siskiyou mat
Endemic
Synonyms: Ceanothus prostratus var. profugus Jepson
Treatment appears in FNA Volume 12. Treatment on page 105. Mentioned on page 95, 96, 100, 101, 106.

Shrubs, 0.1–0.4 m, matlike to moundlike. Stems prostrate to spreading, sometimes rooting at proximal nodes; branchlets reddish-brown, flexible to ± rigid, tomentulose. Leaves not fascicled; petiole 1–2 mm; blade flat to ± cupped, slightly folded lengthwise adaxially, narrowly oblanceolate to narrowly oblong-oblanceolate, 5–15 × 3–6 mm, base cuneate, margins thick to ± revolute, usually denticulate near apex, sometimes entire, teeth (0 or) 2–3, apex usually truncate, sometimes obtuse, abaxial surface pale green, sparsely strigillose to glabrous, adaxial surface green to grayish green, dull, glabrous, sometimes glaucous. Inflorescences axillary, 1–1.7 cm. Flowers: sepals, petals, and nectary pale blue to lavender. Capsules 4–6 mm wide, lobed; valves smooth, horns subapical, minute or weakly developed bulges, intermediate ridges absent. 2n = 24.


Phenology: Flowering Apr–Jun.
Habitat: Rocky soils derived from serpentine, open flats and slopes, chaparral, conifer forests.
Elevation: 100–2200 m.

Discussion

Ceanothus pumilus is endemic to the Klamath Mountains, where it occurs strictly on serpentine soils; it sometimes has been confused with C. arcuatus and C. prostratus, from which it differs principally by its oblanceolate to oblong-lanceolate leaf blades with a truncate, 3-toothed apex.

Hybrids between Ceanothus pumilus and C. cuneatus have been called C. ×humboldtensis Roof.

Selected References

None.

Lower Taxa

None.

"thick" is not a number.

... more about "Ceanothus pumilus"
sparsely strigillose +  and glabrous +
green +  and grayish green +
glaucous +  and glabrous +
perigynous +  and epigynous +
Clifford L. Schmidt† +  and Dieter H. Wilken +
Greene +
cuneate +
Ceanothus sect. Cerastes +
3-veined +  and veined +
not gland-dotted +
0.5 cm5 mm <br />0.005 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
3[-5]-veined +  and pinnate +
spinulose +, spinose +, serrate +  and entire +
denticulate +, dentate +, crenulate +, crenate +  and serrulate +
narrowly oblanceolate;narrowly oblong-oblanceolate +
3mm;6mm +
not thorn-tipped +
0.4 cm4 mm <br />0.004 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
Siskiyou mat +
Calif. +  and Oreg. +
100–2200 m. +
Rocky soils derived from serpentine, open flats and slopes, chaparral, conifer forests. +
subapical +
minute +
free +  and adnate +
0 cm0 mm <br />0 m <br /> (0.05 cm0.5 mm <br />5.0e-4 m <br />) +
unisexual +  and bisexual +
1 cm10 mm <br />0.01 m <br /> (1.7 cm17 mm <br />0.017 m <br />) +
deciduous +  and persistent +
denticulate +
pale blue;lavender +
intrastaminal +
superior +  and inferior +
not fleshy +
perigynous +  and epigynous +
adnate +  and distinct +
6 +  and 5 +
Clawed (?) +, Obovate (?) +  and Spatulate (?) +
0.1 cm1 mm <br />0.001 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
Flowering Apr–Jun. +
2-4-carpellate +
intermediate +
pink +, usually white +  and cream blue or purple +
distinct +
spreading +  and incurved +
6 +  and 5 +
keeled;lanceolate;deltate +
prostrate +  and spreading +
Ceanothus prostratus var. profugus +
Ceanothus pumilus +
Ceanothus subg. Cerastes +
species +
paniclelike +  and racemelike +
not gland-tipped +
unarmed +  and armed +
shrub +  and matlike +
polygamous +, dioecious +  and synoecious +