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island buckwheat, Santa Cruz Island buckwheat, Santa Cruz Island wild buckwheat

St. Catherine's-lace

Habit Shrubs, erect to spreading, 6–15(–20) × 5–30 dm, glabrous and cinereous, reddish. Shrubs, round to erect, 3–20(–35) × (3–)5–20(–35) dm, tomentose to floccose or glabrate, grayish to reddish.
Stems

spreading to erect, occasionally with persistent leaf bases, up to 3/4 or more height of plant;

caudex stems absent;

aerial flowering stems erect, stout, solid, not fistulose, 0.5–1(–1.5) dm, glabrous.

spreading to erect, occasionally with persistent leaf bases, up to 3/4 or more height of plant, often with a distinct main trunk up to 1 dm thick;

caudex stems absent;

aerial flowering stems erect to spreading, slender to stout, solid, not fistulose, 1–4 dm, tomentose to glabrate.

Leaves

cauline, 1 per node;

petiole 0.1–0.5 cm, tomentose;

blade linear to narrowly oblong, 2–4(–5) × 0.1–0.4(–0.6) cm, white-tomentose abaxially, cinereous to glabrate and greenish adaxially, margins often revolute.

cauline, 1 per node;

petiole 0.5–4 cm, tomentose;

blade oblong-ovate to ovate or lanceolate to narrowly oblong, 2.5–7(–10) × 1–5 cm, white-tomentose abaxially, sometimes slightly less so or cinereous to somewhat glabrate and greenish adaxially, margins plane, sometimes crisped.

Inflorescences

cymose, 5–10 × 5–15(–20) cm;

branches dichotomous, glabrous;

bracts 1–3, leaflike, lanceolate to oblong, 0.5–2 × 0.3–1.5 cm.

cymose, open or compact, 5–30 × (2–)5–50(–80) cm;

branches dichotomous, tomentose to floccose or glabrate;

bracts 3, scalelike, broadly triangular, and 1–2 mm, or leaflike, oblanceolate to elliptic, and 5–30 mm.

Peduncles

absent or erect, stout, 0.1–0.5 cm, cinereous.

absent or erect, slender, 0.1–0.5 cm, tomentose.

Involucres

1 per node, campanulate, 2–3 × 2.5–4 mm, cinereous;

teeth 5–7, erect, 0.5–1.5 mm.

1 per node, campanulate, 3–5 × 2.5–4 mm, tomentose;

teeth 5, erect, 0.3–0.8 mm.

Flowers

2–3.5(–4) mm;

perianth white to pinkish, villous abaxially;

tepals connate proximally, monomorphic, oblanceolate to narrowly obovate;

stamens exserted, 3–5 mm;

filaments glabrous.

2–4 mm;

perianth white to rose, white-villous abaxially;

tepals connate proximal 1/4, monomorphic, obovate;

stamens exserted, 2–4 mm;

filaments pilose proximally.

Achenes

brown, 2.5–3.5 mm, glabrous.

brown, 2–3.5 mm, glabrous.

2n

= 40.

Eriogonum arborescens

Eriogonum giganteum

Phenology Flowering Apr–Oct.
Habitat Rocky slopes and canyon walls, coastal scrub communities
Elevation 10-600 m (0-2000 ft)
Distribution
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
Discussion

Of conservation concern.

Eriogonum arborescens is local and occasionally rare on Santa Cruz, Santa Rosa, and Anacapa islands in Santa Cruz and Ventura counties. The species is cultivated, and populations have become naturalized on the mainland from San Mateo County south to San Diego, in large part because of planting along highways. Every effort should be made to remove these naturalized populations from the mainland.

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

Varieties 3 (3 in the flora).

The California Department of Transportation is planting members of this insular species, especially var. giganteum, on the mainland, where it readily hybridizes with both E. fasciculatum and E. cinereum. Every effort should be made to remove the introduced E. giganteum from coastal California.

The Avalon scrub-hairstreak butterfly (Strymon avalona), which is endemic to Santa Catalina Island, uses Eriogonum giganteum as a food plant.

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

Key
1. Leaf blades oblong-lanceolate to lanceolate; San Clemente Island
var. formosum
1. Leaf blades oblong-ovate to ovate; not San Clemente Island
→ 2
2. Leaf blades 3-7(-10) × 2-5 cm; inflorescences open; Santa Catalina Island
var. giganteum
2. Leaf blades 2.5-3.5(-6) × 1.5-2(-4) cm; inflorescences compact to rarely open; Santa Barbara and Sutil islands
var. compactum
Source FNA vol. 5, p. 302. FNA vol. 5, p. 301.
Parent taxa Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Eucycla Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Eucycla
Sibling taxa
E. abertianum, E. acaule, E. alatum, E. aliquantum, E. allenii, E. alpinum, E. ammophilum, E. ampullaceum, E. androsaceum, E. anemophilum, E. angulosum, E. annuum, E. apiculatum, E. apricum, E. arcuatum, E. aretioides, E. argillosum, E. argophyllum, E. arizonicum, E. artificis, E. atrorubens, E. baileyi, E. batemanii, E. bicolor, E. bifurcatum, E. brachyanthum, E. brachypodum, E. brandegeei, E. breedlovei, E. brevicaule, E. butterworthianum, E. caespitosum, E. capillare, E. cernuum, E. chrysops, E. cinereum, E. cithariforme, E. clavatum, E. clavellatum, E. codium, E. collinum, E. coloradense, E. compositum, E. concinnum, E. congdonii, E. contiguum, E. contortum, E. correllii, E. corymbosum, E. covilleanum, E. crocatum, E. cronquistii, E. crosbyae, E. cusickii, E. darrovii, E. dasyanthemum, E. davidsonii, E. deflexum, E. deserticola, E. desertorum, E. diatomaceum, E. diclinum, E. divaricatum, E. douglasii, E. eastwoodianum, E. effusum, E. elatum, E. elegans, E. elongatum, E. ephedroides, E. eremicola, E. eremicum, E. ericifolium, E. esmeraldense, E. evanidum, E. exaltatum, E. exilifolium, E. fasciculatum, E. flavum, E. fusiforme, E. giganteum, E. gilmanii, E. glandulosum, E. gordonii, E. gossypinum, E. gracile, E. gracilipes, E. gracillimum, E. grande, E. greggii, E. gypsophilum, E. havardii, E. heermannii, E. helichrysoides, E. hemipterum, E. heracleoides, E. hieracifolium, E. hirtellum, E. hirtiflorum, E. hoffmannii, E. holmgrenii, E. hookeri, E. howellianum, E. hylophilum, E. incanum, E. inerme, E. inflatum, E. intrafractum, E. jamesii, E. jonesii, E. kelloggii, E. kennedyi, E. kingii, E. lachnogynum, E. lancifolium, E. latens, E. latifolium, E. lemmonii, E. leptocladon, E. leptophyllum, E. libertini, E. lobbii, E. loganum, E. lonchophyllum, E. longifolium, E. luteolum, E. maculatum, E. mancum, E. marifolium, E. mensicola, E. microthecum, E. mitophyllum, E. mohavense, E. molestum, E. mortonianum, E. multiflorum, E. natum, E. nealleyi, E. nervulosum, E. nidularium, E. niveum, E. nortonii, E. novonudum, E. nudum, E. nummulare, E. nutans, E. ochrocephalum, E. ordii, E. ostlundii, E. ovalifolium, E. palmerianum, E. panamintense, E. panguicense, E. parishii, E. parvifolium, E. pauciflorum, E. pelinophilum, E. pendulum, E. pharnaceoides, E. plumatella, E. polycladon, E. polypodum, E. prattenianum, E. prociduum, E. pulchrum, E. pusillum, E. pyrolifolium, E. racemosum, E. reniforme, E. ripleyi, E. rixfordii, E. robustum, E. rosense, E. roseum, E. rotundifolium, E. rubricaule, E. rupinum, E. salicornioides, E. saxatile, E. scabrellum, E. scopulorum, E. shockleyi, E. siskiyouense, E. smithii, E. soliceps, E. soredium, E. spathulatum, E. spectabile, E. spergulinum, E. sphaerocephalum, E. strictum, E. subreniforme, E. suffruticosum, E. temblorense, E. tenellum, E. ternatum, E. terrenatum, E. thomasii, E. thompsoniae, E. thornei, E. thurberi, E. thymoides, E. tiehmii, E. tomentosum, E. trichopes, E. tripodum, E. truncatum, E. tumulosum, E. twisselmannii, E. umbellatum, E. ursinum, E. vestitum, E. villiflorum, E. vimineum, E. viridescens, E. viridulum, E. viscidulum, E. visheri, E. watsonii, E. wetherillii, E. wootonii, E. wrightii, E. zionis
E. abertianum, E. acaule, E. alatum, E. aliquantum, E. allenii, E. alpinum, E. ammophilum, E. ampullaceum, E. androsaceum, E. anemophilum, E. angulosum, E. annuum, E. apiculatum, E. apricum, E. arborescens, E. arcuatum, E. aretioides, E. argillosum, E. argophyllum, E. arizonicum, E. artificis, E. atrorubens, E. baileyi, E. batemanii, E. bicolor, E. bifurcatum, E. brachyanthum, E. brachypodum, E. brandegeei, E. breedlovei, E. brevicaule, E. butterworthianum, E. caespitosum, E. capillare, E. cernuum, E. chrysops, E. cinereum, E. cithariforme, E. clavatum, E. clavellatum, E. codium, E. collinum, E. coloradense, E. compositum, E. concinnum, E. congdonii, E. contiguum, E. contortum, E. correllii, E. corymbosum, E. covilleanum, E. crocatum, E. cronquistii, E. crosbyae, E. cusickii, E. darrovii, E. dasyanthemum, E. davidsonii, E. deflexum, E. deserticola, E. desertorum, E. diatomaceum, E. diclinum, E. divaricatum, E. douglasii, E. eastwoodianum, E. effusum, E. elatum, E. elegans, E. elongatum, E. ephedroides, E. eremicola, E. eremicum, E. ericifolium, E. esmeraldense, E. evanidum, E. exaltatum, E. exilifolium, E. fasciculatum, E. flavum, E. fusiforme, E. gilmanii, E. glandulosum, E. gordonii, E. gossypinum, E. gracile, E. gracilipes, E. gracillimum, E. grande, E. greggii, E. gypsophilum, E. havardii, E. heermannii, E. helichrysoides, E. hemipterum, E. heracleoides, E. hieracifolium, E. hirtellum, E. hirtiflorum, E. hoffmannii, E. holmgrenii, E. hookeri, E. howellianum, E. hylophilum, E. incanum, E. inerme, E. inflatum, E. intrafractum, E. jamesii, E. jonesii, E. kelloggii, E. kennedyi, E. kingii, E. lachnogynum, E. lancifolium, E. latens, E. latifolium, E. lemmonii, E. leptocladon, E. leptophyllum, E. libertini, E. lobbii, E. loganum, E. lonchophyllum, E. longifolium, E. luteolum, E. maculatum, E. mancum, E. marifolium, E. mensicola, E. microthecum, E. mitophyllum, E. mohavense, E. molestum, E. mortonianum, E. multiflorum, E. natum, E. nealleyi, E. nervulosum, E. nidularium, E. niveum, E. nortonii, E. novonudum, E. nudum, E. nummulare, E. nutans, E. ochrocephalum, E. ordii, E. ostlundii, E. ovalifolium, E. palmerianum, E. panamintense, E. panguicense, E. parishii, E. parvifolium, E. pauciflorum, E. pelinophilum, E. pendulum, E. pharnaceoides, E. plumatella, E. polycladon, E. polypodum, E. prattenianum, E. prociduum, E. pulchrum, E. pusillum, E. pyrolifolium, E. racemosum, E. reniforme, E. ripleyi, E. rixfordii, E. robustum, E. rosense, E. roseum, E. rotundifolium, E. rubricaule, E. rupinum, E. salicornioides, E. saxatile, E. scabrellum, E. scopulorum, E. shockleyi, E. siskiyouense, E. smithii, E. soliceps, E. soredium, E. spathulatum, E. spectabile, E. spergulinum, E. sphaerocephalum, E. strictum, E. subreniforme, E. suffruticosum, E. temblorense, E. tenellum, E. ternatum, E. terrenatum, E. thomasii, E. thompsoniae, E. thornei, E. thurberi, E. thymoides, E. tiehmii, E. tomentosum, E. trichopes, E. tripodum, E. truncatum, E. tumulosum, E. twisselmannii, E. umbellatum, E. ursinum, E. vestitum, E. villiflorum, E. vimineum, E. viridescens, E. viridulum, E. viscidulum, E. visheri, E. watsonii, E. wetherillii, E. wootonii, E. wrightii, E. zionis
Subordinate taxa
E. giganteum var. compactum, E. giganteum var. formosum, E. giganteum var. giganteum
Name authority Greene: Bull. Calif. Acad. Sci. 1: 11. (1884) S. Watson: Proc. Amer. Acad. Arts 20: 371. (1885)
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