ceanothus

leaves opposite, 1-ribbed from base

musk brush
Ceanothus jepsonii

• twig: generally brown
• leaf blade:
• 10–20 mm long, 5–13 mm wide, ± folded lengthwise
• no other leaves are folded lengthwise
• adaxially yellow-green, glabrous
• abaxially ± short-strigose between veins
• margin thick to ± rolled-under, wavy, toothed with 7–11 spines
• others may be toothed, but do not have spines
• Mt. Tam

buckbrush
Ceanothus cuneatus

buckbrush
Ceanothus cuneatus

• twig: generally brown to gray-brown, glabrous to sparsely puberulent
• leaf blade:
• occasionally clustered
• others never clustered?
• 6–30 mm long, 3–18 mm wide
• adaxially dull green, glabrous
• abaxially paler, glabrous to ± strigose
• margin entire or < 5 teeth near tip [not glandular]

coyote ceanothus
Ceanothus ferrisiae

• twig: brown to gray-brown, generally ± short-hairy, not angled
• leaf blade:
• 12–25 mm long, 7–18 mm wide
• adaxially dark green, glabrous
• abaxially paler, short-strigose between evident veins
• margin entire or with 5–35 ± sharp teeth ± evenly distributed
• possibly only historical; near Anderson Lake

point reyes ceanothus
Ceanothus gloriosus

• twig: green, red-brown, or brown, generally angled near tips
• leaf blade
• 13–45 mm long, 5–24 mm wide
• adaxially dark green, glabrous
• abaxially glabrous to puberulent
• margin 13–35 toothed, ± evenly distributed
• rare:Mt. Tamalpais

mason’s ceanothus
Ceanothus masonii

• twig: red-brown to dark brown or gray-brown, generally angled near tips
• leaf blad:
• 7–21 mm long, 4–13 mm wide
• adaxially dark green, glabrous
• abaxially short-strigose
• margin 9–17 toothed, ± evenly distributed
• may be same species as point reyes ceanothus (Ceanothus gloriosus)
• rare: Mt. Tamalpais

leaves alternate, 1-ribbed from base

wartleaf ceanothus
Ceanothus papillosus

wartleaf ceanothus
Ceanothus papillosus

• twig: green to gray-brown
• leaf blade:
• 11–50 mm long, 6–15 mm wide
• adaxially dark green, glandular-papillate (warty)
• abaxially paler, generally densely hairy
• margin rolled under, minutely gland-toothed, teeth 17–31
• Flower: deep blue

wavyleaf ceanothus
Ceanothus foliosus

• twig: green to red-green, [not ridged]
• leaf blade:
• 5–20 mm long, 3–13 mm wide, ± folded lengthwise
• 1-ribbed or faintly 3-ribbed from base
• adaxially dark green
• abaxially paler, glabrous to puberulent
• margin not rolled under, local varieties are gland-toothed, teeth 31–42
• mostly historical except at Mt. Madonna and Mt. Tamalpais

deerbrush ceanothus
Ceanothus integerrimus var. integerrimus

• twig: generally green
• leaf blade:
• 15–53 mm long, 10–45 mm wide
• adaxially dull green, glabrous to puberulent
• abaxially pale green, glabrous to sparsely short-hairy
• margin generally entire, not rolled under
• mostly Sierra Azul, Big Basin, and Soquel

leaves alternate, 3-ribbed from base

tobacco brush
Ceanothus velutinus

• twig: green to red-brown, flexible
• leaf blade:
• 33–75 mm long, 13–55 mm wide, leathery
• adaxially shiny green, glabrous, ± sticky
• abaxially glabrous to ± puberulent
• margin minutely gland-toothed, teeth 90–150+
• Mt. Tamalpais

blueblossom
Ceanothus thyrsiflorus

blueblossom
Ceanothus thyrsiflorus

• corolla blue to white
• twig: green, flexible, ridged, angled distally, [glabrous]
• leaf blade:
• 10–39 mm long, 5–20 mm wide
• adaxially dark green, glabrous
• abaxially paler, glabrous to puberulent, veins ± raised
• margin ± gland-toothed

jimbrush
Ceanothus oliganthus var. sorediatus

jimbrush
Ceanothus oliganthus var. sorediatus

• twig: green to reddish, flexible, not ridged or angled, [may be hairy]
• leaf blade:
• 11–30 mm long, 5–25 mm wide
• adaxially dark green, ± glabrous to short-hairy
• abaxially paler, sparsely to densely short-hairy, especially veins
• margin minutely gland-toothed, teeth 20–70

coast whitethorn
Ceanothus incanus

• twig: pale gray to gray-green, rigid, thorn-like or not
• leaf blade:
• 20–50+ mm long, 10–45 mm wide, generally larger than chaparral whitethorn (Ceanothus leucodermis)
• 3-ribbed from base
• adaxially dull green, glabrous to sparsely puberulent
• abaxially gray-green, strigose
• margin generally entire
• uncommon: Santa Cruz Range

chaparral whitethorn
Ceanothus leucodermis

• twig: pale gray to gray-green, rigid, thorn-like
• except where stated, all other twigs are flexible, not thorn-like
• leaf blade:
• 12–30 mm long, 3–15 mm wide. generally smaller than coast whitethorn (Ceanothus incanus)
• 3-ribbed from base
• adaxially dull green, glabrous to sparsely puberulent
• abaxially ± strigose, especially veins
• margin entire to ± glandular-serrate
• rare

hybrids

Ceanothus hybrids aren’t rare. Recent observations seem to find them especially in recovering burned areas. Because the hybrids can have any mix of characters, they do not key easily. E.g. this histogram of wartleaf vs. blueblossom characteristics.

Ceanothus × regius

Ceanothus × regius

• cross of blueblossom (Ceanothus thyrsiflorus var. thyrsiflorus) and wartleaf ceanothus (Ceanothus papillosus)
• may have any combination of characteristics from each
• e.g. mix of 1-ribbed and 3-ribbed leaves, twigs somewhat ridged, warts only at leaf margins