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chaparral yucca, our lord's candle

chaparral yucca, hesperoyucca, our lord's candle, Quixote plant

Habit Plants monocarpic or polycarpic, sometimes rhizomatous, some with secondary rosettes at base or stems branching to form new rosettes after flowering; rosettes single or cespitose, in small to very large, compact or open communities, or occasionally solitary. Plants simple or cespitose, erect, acaulescent, scapose, rosulate, monocarpic or polycarpic; rosettes solitary or in colonies.
Leaves

20–90(–125) × 0.7–2 cm wide at base in narrow forms, 2–2.5 cm in broader forms.

blades linear, rarely narrowly lanceolate, widest at base, tapering to apex, glaucous, somewhat flexible when young, rigid at maturity, margins pale yellow, mostly denticulate, corneous, apex distinctly spinose.

Scape

0.9–3 m × 2.5–15 cm diam. near base.

well developed, extending beyond rosettes, usually more than 2.5 cm in diam., glabrous.

Inflorescences

1 when rosette solitary, 1–many per rosette when rosettes in colonies, 2.5–28 × 1.5–7 dm at widest point.

paniculate, cylindrical, bracteate, glabrous;

rachis and peduncle reddish purple;

bracts reflexed, deltate, abruptly narrowing to linear, sharp-pointed apex.

Flowers

bisexual;

perianth campanulate or globose;

tepals distinct, white or creamy white to greenish or purple-tinged, broadly lanceolate, 3.2–4.5(–6) cm;

filaments ca. 1.3 cm, equal to or longer than pistil, papillose;

anthers reniform;

pistil 1–1.3 × 0.6–1 cm;

ovary superior;

style white, 2–3 mm;

stigmas green, capitate.

Fruits

erect, capsular, obovoid, 3–5 × 1.5–4 cm, dehiscence loculicidal.

Capsules

with conspicuous placental wings at maturity.

Seeds

many per locule, dull black, thin, flattened, 6–8 mm diam. x = 30.

Hesperoyucca whipplei

Hesperoyucca

Phenology Flowering spring.
Habitat Desert, chaparral, desert woodland coastal sage
Elevation 300–2500 m (1000–8200 ft)
Distribution
from FNA
CA; Mexico (Baja California)
[WildflowerSearch map]
[BONAP county map]
from USDA
w United States; nw Mexico
[BONAP county map]
Discussion

Within Hesperoyucca whipplei, W. Trelease (1893) recognized two varieties, A. L. Haines (1941) and P. A. Munz (1959) each recognized five subspecies, and J. M. Webber (1953) recognized four varieties based on growth form. Others (S. D. McKelvey 1938–1947; K. K. McKinney and J. C. Hickman 1993) have argued that growth form in this species is highly variable, and have questioned the desirability of recognizing any infraspecific taxa at all in H. whipplei.

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

Species 3 (2 in the flora).

DNA evidence (M. A. Hanson 1993; D. J. Bogler 1994; K. H. Clary 1997) supports W. Trelease’s (1893) recognition of Hesperoyucca at the genus level and reinforces S. D. McKelvey’s (1938–1947, vol. 2) statement that several characteristics of Hesperoyucca whipplei are not typical of Yucca and could justify its removal from Yucca.

J. M. Webber (1953) believed that the differences in leaf, inflorescence, and capsule that McKelvey used to separate Hesperoyucca newberryi from H. whipplei are weak and within the normal ranges of variation in the latter species. F. Hochstätter (2000) treated H. newberryi as a subspecies of H. whipplei. DNA evidence (K. H. Clary 1997) supports specific status for H. newberryi, H. whipplei, and a third species from Mexico, H. peninsularis (McKelvey) Clary. Conclusive DNA analyses have not been performed on the proposed varieties and subspecies of H. whipplei (K. H. Clary 2001), nor has there been any recent systematic morphological work that would support those earlier proposals. For these reasons, only the species of Hesperoyucca are described. This treatment follows S. D. McKelvey’s and K. H. Clary’s interpretations.

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

Key
1. Mature capsules with conspicuous placental wings; plants monocarpic and rosettes single, or plants polycarpic and rosettes cespitose; sw California
H. whipplei
1. Mature capsules with slight or inconspicuous placental wings; plants monocarpic, rosettes single; Arizona.
H. newberryi
Source FNA vol. 26, p. 440. FNA vol. 26, p. 439. Author: Karen H. Clary.
Parent taxa Agavaceae > Hesperoyucca Agavaceae
Sibling taxa
H. newberryi
Subordinate taxa
H. newberryi, H. whipplei
Synonyms Yucca whipplei, H. whipplei var. graminifolia, Yucca californica, Yucca graminifolia, Yucca nitida, Yucca ortgensiana, Yucca whipplei subsp. caespitosa, Yucca whipplei var. caespitosa, Yucca whipplei subsp. intermedia, Yucca whipplei var. intermedia, Yucca whipplei subsp. parishii, Yucca whipplei var. parishii, Yucca whipplei subsp. percursa, Yucca whipplei var. percursa Yucca unranked H.
Name authority (Torrey) Trelease: Rep. (Annual) Missouri Bot. Gard 4: 208. (1893) (Engelmann) Baker: Bull. Misc. Inform. Kew 1892: 8. (1892)
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