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prostrate clarkia

gunsight clarkia, Xantus' clarkia

Stems

prostrate or decumbent, to 50 cm, sparsely puberulent.

erect, to 80 cm, glabrous, glaucous.

Leaves

sessile or subsessile;

blade oblanceolate to elliptic, 1–2.5 cm, apex usually obtuse.

petiole 0–2 mm;

blade linear to lanceolate, 2–6 cm.

Inflorescences

prostrate, dense racemes, axis straight;

buds erect.

open racemes, axis straight;

buds pendent.

Flowers

floral tube 4–7 mm;

sepals usually reflexed in pairs;

corolla bowl-shaped, petals lavender-pink shading pale yellow basally, with reddish purple spot above base, 10–15 mm;

stamens 8, subequal;

ovary 8-grooved;

stigma not exserted beyond anthers.

floral tube 2–5 mm;

sepals reflexed together to 1 side;

corolla rotate, petals lavender to reddish purple, lavender-pink, or white, often with white-surrounded dark reddish purple spot distally, clawed, 2-lobed, with slender central tooth, 1–3 mm, 6–20 mm;

stamens 8, in 2 unequal sets, outer anthers lavender to purple, inner smaller, paler;

ovary 8-grooved;

stigma exserted or not beyond anthers.

Capsules

20–30 mm.

15–25 mm;

pedicel 0–5 mm.

Seeds

brown or gray, 1–1.5 mm, scaly, crest 0.2 mm.

brown, 1.3–1.5 mm, tuberculate, crest minute.

2n

= 52.

Clarkia prostrata

Clarkia xantiana

Phenology Flowering May–Jul.
Habitat Coastal bluffs in grasslands and closed-cone pine forests.
Elevation 0–100 m. (0–300 ft.)
Distribution
from FNA
CA
[BONAP county map]
from USDA
California
[WildflowerSearch map]
[BONAP county map]
Discussion

Clarkia prostrata, like C. davyi, occurs only on coastal bluffs and adjacent low elevation pine forests along the Pacific coast, and in this case only in the California Central Coast Subregion in Monterey, Santa Barbara, Santa Cruz, and San Luis Obispo counties.

Clarkia prostrata is a hexaploid that combines the tetraploid genome of C. davyi and the diploid genome of C. speciosa. Clarkia prostrata is morphologically and ecologically very similar to C. davyi but can usually be distinguished by its larger flowers with a spot on each petal. It differs from C. speciosa by having smaller flowers with the stigma not exserted beyond the anthers.

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

Subspecies 2 (2 in the flora).

Originally placed in the group now delimited as subsect. Phaeostoma by H. Lewis and M. E. Lewis (1955), Clarkia xantiana was treated as a monotypic subsect. Xantianae within sect. Phaeostoma by K. E. Holsinger (1985), based mainly on its unusual 2-lobed petals with a tooth in the sinus. Molecular data (R. A. Levin et al. 2004) placed C. xantiana close to C. bottae, and both of them close to but not within sect. Phaeostoma. Both species share the chromosome number 2n = 18 with C. jolonensis.

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

Key
1. Petals 12–20 mm; stigmas exserted beyond anthers.
subsp. xantiana
1. Petals 6–12 mm; stigmas not exserted beyond anthers.
subsp. parviflora
Source FNA vol. 10. FNA vol. 10.
Parent taxa Onagraceae > subfam. Onagroideae > tribe Onagreae > Clarkia > sect. Godetia Onagraceae > subfam. Onagroideae > tribe Onagreae > Clarkia > sect. Fibula
Sibling taxa
C. affinis, C. amoena, C. arcuata, C. australis, C. biloba, C. borealis, C. bottae, C. breweri, C. concinna, C. cylindrica, C. davyi, C. delicata, C. dudleyana, C. epilobioides, C. exilis, C. franciscana, C. gracilis, C. heterandra, C. imbricata, C. jolonensis, C. lassenensis, C. lewisii, C. lingulata, C. mildrediae, C. modesta, C. mosquinii, C. pulchella, C. purpurea, C. rhomboidea, C. rostrata, C. rubicunda, C. similis, C. speciosa, C. springvillensis, C. stellata, C. tembloriensis, C. unguiculata, C. virgata, C. williamsonii, C. xantiana
C. affinis, C. amoena, C. arcuata, C. australis, C. biloba, C. borealis, C. bottae, C. breweri, C. concinna, C. cylindrica, C. davyi, C. delicata, C. dudleyana, C. epilobioides, C. exilis, C. franciscana, C. gracilis, C. heterandra, C. imbricata, C. jolonensis, C. lassenensis, C. lewisii, C. lingulata, C. mildrediae, C. modesta, C. mosquinii, C. prostrata, C. pulchella, C. purpurea, C. rhomboidea, C. rostrata, C. rubicunda, C. similis, C. speciosa, C. springvillensis, C. stellata, C. tembloriensis, C. unguiculata, C. virgata, C. williamsonii
Subordinate taxa
C. xantiana subsp. parviflora, C. xantiana subsp. xantiana
Name authority H. Lewis & M. E. Lewis: Madroño 12: 36. (1953) A. Gray: Proc. Boston Soc. Nat. Hist. 7: 146. (1859)
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