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wartleaf ceanothus

Otay Mountain ceanothus

Habit Shrubs, evergreen, 1–5 m. Stems erect to ascending, not rooting at nodes; branchlets green to reddish brown, not thorn-tipped, round in cross section, ± flexible to rigid, densely tomentulose. Shrubs, 1–3.5 m. Stems erect to ascending, not rooting at nodes; branchlets grayish brown to brown, ± flexible to rigid, tomentulose.
Leaves

petiole 1–3 mm;

blade cupped to flat, linear, narrowly oblong, or oblong-elliptic, 12–50 × 6–15 mm, base obtuse to rounded, margins minutely glandular-denticulate, revolute, glands 17–31, apex obtuse, truncate, or retuse, abaxial surface pale green, densely villosulous to tomentulose, adaxial surface dark green, sparsely puberulent and glandular-papillate; pinnately veined.

not fascicled;

petiole 0–2 mm;

blade flat to ± cupped, widely elliptic to obovate, 5–13 × 4–10 mm, base cuneate, margins revolute, sometimes wavy, coarsely denticulate near apex, teeth 3–5, apex truncate, retuse, or cuspidate, abaxial surface green, tomentulose, adaxial surface green, glabrous or sparsely puberulent.

Inflorescences

axillary or terminal, racemelike, 2–8 cm.

axillary or terminal, 0.6–1.8 cm.

Flowers

sepals, petals, and nectary deep blue.

sepals and petals white;

nectary tan to brown.

Capsules

2–3 mm wide, lobed;

valves smooth, viscid when young, not or weakly crested.

4–6 mm wide, weakly lobed;

valves smooth, horns minute or absent, intermediate ridges absent.

2n

= 24.

Ceanothus papillosus

Ceanothus otayensis

Phenology Flowering Mar–May. Flowering Jan–Apr.
Habitat Rocky ridges, slopes, and flats, chaparral, mixed evergreen forests. Rocky slopes, chaparral.
Elevation 20–1500 m. (100–4900 ft.) 500–1100 m. (1600–3600 ft.)
Distribution
from FNA
CA; Mexico (Baja California)
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; Mexico (Baja California)
[BONAP county map]
Discussion

Ceanothus papillosus occurs in the Coast Ranges from San Francisco Bay south to the Santa Ynez Mountains, Ventura County, with disjunct populations in the Santa Ana Mountains, California, and Cerro Bola, in northern Baja California. The name C. papillosus var. roweanus was originally applied to low-growing plants with ascending to spreading, arcuate branches (H. McMinn 1939). M. Van Rensselaer and McMinn (1942) later emended the circumscription to include plants with linear leaves and retuse to truncate leaf apices, but these are found throughout the range of the species. Leaves with obtuse to truncate or retuse leaf apices also can be found on the same plant. Putative hybrids with C. integerrimus and C. oliganthus have been documented (McMinn 1944). Hybrids with C. thyrsiflorus have been named C. ×regius (Jepson) McMinn. Some putatively advanced generation hybrids have narrowly elliptic, weakly papillate leaves with obtuse apices, and sometimes have been misinterpreted as belonging to C. papillosus.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Ceanothus otayensis is known from the Otay and San Miguel Mountains, southern San Diego County, with at least one locality in northern Baja California. McMinn described C. otayensis as a hybrid between C. crassifolius and C. perplexans. However, neither of the putative parents occurs sympatrically with C. otayensis, and its populations do not display the increased variation expected from hybridization.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 12, p. 92. FNA vol. 12, p. 108.
Parent taxa Rhamnaceae > Ceanothus > subg. Ceanothus Rhamnaceae > Ceanothus > subg. Cerastes
Sibling taxa
C. americanus, C. arboreus, C. arcuatus, C. confusus, C. cordulatus, C. crassifolius, C. cuneatus, C. cyaneus, C. dentatus, C. divergens, C. diversifolius, C. fendleri, C. ferrisiae, C. foliosus, C. fresnensis, C. gloriosus, C. griseus, C. hearstiorum, C. herbaceus, C. impressus, C. incanus, C. integerrimus, C. jepsonii, C. lemmonii, C. leucodermis, C. maritimus, C. martini, C. masonii, C. megacarpus, C. microphyllus, C. oliganthus, C. ophiochilus, C. otayensis, C. palmeri, C. parryi, C. parvifolius, C. pauciflorus, C. perplexans, C. pinetorum, C. prostratus, C. pumilus, C. purpureus, C. roderickii, C. sanguineus, C. sonomensis, C. spinosus, C. thyrsiflorus, C. tomentosus, C. velutinus, C. verrucosus
C. americanus, C. arboreus, C. arcuatus, C. confusus, C. cordulatus, C. crassifolius, C. cuneatus, C. cyaneus, C. dentatus, C. divergens, C. diversifolius, C. fendleri, C. ferrisiae, C. foliosus, C. fresnensis, C. gloriosus, C. griseus, C. hearstiorum, C. herbaceus, C. impressus, C. incanus, C. integerrimus, C. jepsonii, C. lemmonii, C. leucodermis, C. maritimus, C. martini, C. masonii, C. megacarpus, C. microphyllus, C. oliganthus, C. ophiochilus, C. palmeri, C. papillosus, C. parryi, C. parvifolius, C. pauciflorus, C. perplexans, C. pinetorum, C. prostratus, C. pumilus, C. purpureus, C. roderickii, C. sanguineus, C. sonomensis, C. spinosus, C. thyrsiflorus, C. tomentosus, C. velutinus, C. verrucosus
Synonyms C. papillosus subsp. roweanus, C. papillosus var. roweanus
Name authority Torrey & A. Gray: Fl. N. Amer. 1: 268. (1838) McMinn: in M. van Rensselaer and H. McMinn, Ceanothus, 273, fig. 102. (1942) — as hybrid
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