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cancer root, ghost pipe, naked broomrape, one-flower broom-rape, one-flower cancer-root, orobanche uniflore, small cancer-root

Cooper's broomrape, desert broomrape

Habit Plants simple or few-branched basally, sometimes forked medially, 3.5–18(–25) cm (including pedicels), stem portion 1–5(–7) cm, slender, base not enlarged. Plants simple, branched, or multiple stems from host attachment, 5–45 cm, stout, sometimes slender, base usually enlarged.
Roots

inconspicuous, slender or stout, unbranched or few-branched.

usually relatively conspicuous (often forming an irregular mass), slender, branched.

Leaves

relatively few, loosely imbricate or more remote, loosely ascending to spreading;

blade oblong-lanceolate to awl-shaped, 2–10 mm, margins entire, often inrolled, apex acuminate, surfaces glabrous.

numerous, appressed;

blade ± lanceolate to broadly ovate, 6–12 mm, margins entire, apex acute or obtuse, surfaces sometimes glandular-pubescent.

Inflorescences

of solitary flowers or fascicles of 2(–4) at stem or branch tips, white to cream, sometimes purple tinged, simple, glabrous;

bracts loosely ascending and erect, oblanceolate to broadly ovate, obovate, rhombic, or awl-shaped, 5–12 mm, apex acute to acuminate, glabrous, rarely glandular-pubescent distally.

spikelike racemes, purple, usually branched, densely glandular-pubescent, sometimes appearing canescent;

flowers numerous;

bracts erect to reflexed, lanceolate to linear, 5–12 mm, apex acuminate, obtuse, or acute, glandular-pubescent.

Pedicels

(8–)20–110(–170) mm, much longer than plant axis;

bracteoles 0.

0–30 mm, much shorter than plant axis;

bracteoles 2.

Flowers

calyx white to straw colored or light yellow, or pale to dark, dull purple, sometimes brownish, ± radially symmetric, 4–12(–15) mm, divided into 5 subequal lobes, lobes slightly shorter than to 2 times as long as tube, ± triangular or subulate-triangular, sparsely to moderately glandular-pubescent;

corolla (11–)15–30(–35) mm, tube white to purple, blue, or yellow, sometimes lighter proximally or with light or darker purple or blue veins, slightly to moderately constricted above ovary, ± bent forward, glandular-pubescent;

palatal folds ± prominent, bright yellow, glandular- and/or eglandular-pubescent, sometimes glabrescent;

lips white, yellow, purple, or blue, sometimes with light or darker purple or blue veins, abaxial lip slightly to moderately spreading, sometimes ± recurved distally, (1–)2–6(–9) mm, lobes oblong-obovate to nearly round, apex rounded to bluntly pointed or shallowly emarginate (sometimes with 2 notches), adaxial lip slightly to moderately spreading, sometimes recurved, 2–6(–9) mm, lobes broadly oblong-ovate to oblong-semiorbiculate, apex rounded, rarely bluntly pointed or shallowly emarginate;

filaments glabrous, anthers included, glabrous or villous-tomentose.

calyx dark purple or lavender, weakly bilaterally symmetric, 8–12 mm, deeply divided into 5 lobes, lobes lanceolate-acute to -attenuate, densely glandular-pubescent;

corolla 15–32 mm, tube purple or lavender, rarely white, tinged with purple, constricted above ovary, bent forward, ± glandular-pubescent;

palatal folds prominent, yellow, densely pubescent;

lips dark purple to lavender, with darker purple veins, abaxial lip spreading or slightly reflexed, 3–9 mm, lobes oblong-lanceolate to narrowly ovate, apex acute, often with apiculate tooth, adaxial lip erect, reflexed, or revolute, 6–10 mm, lobes ± triangular, rarely truncate, apex acute, often with apiculate teeth;

filaments glabrous, anthers included, glabrous, sparsely villous, pubescent, or tomentulose along sutures, usually also with inconspicuous stalked glands (these minute, appearing peglike under magnification).

Capsules

ovoid to oblong-ovoid, 4–8(–11) mm.

ovoid, 6–12 mm.

Seeds

0.1–0.4 mm.

0.2–0.5 mm.

Orobanche uniflora

Orobanche cooperi

Distribution
from FNA
AK; AR; AZ; CA; CO; CT; DC; DE; FL; IA; ID; IL; IN; KS; KY; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; TN; TX; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; NB; NF; NS; ON; PE; QC; SK; Mexico
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CA; NM; NV; TX; n Mexico
[WildflowerSearch map]
[BONAP county map]
Discussion

Subspecies 2 (2 in the flora).

Orobanche uniflora forms a polymorphic complex that requires more detailed study. The detection of broad-scale patterns of morphological variation is confounded by the differentiation among local races. D. M. Achey (1933) recognized five varieties, and K. C. Watson (1975), in her unpublished thesis, revised the classification to three subspecies. The present treatment, which accepts only the two major infraspecific variants as subspecies, should be considered highly tentative.

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

Subspecies 3 (3 in the flora).

The hosts for Orobanche cooperi are shrubs of Ambrosia and Viguiera (Asteraceae).

L. R. Heckard and T. I. Chuang (1975) mentioned an undescribed polyploid variant (2n = 96) with smaller, shorter-lobed corollas and peltate, bowl-shaped stigmas occurs on the same hosts in southern California.

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

Key
1. Calyx lobes slightly shorter than to only slightly longer than tubes, narrowly to broadly lanceolate-triangular; corollas white to pale yellow, sometimes pale purplish tinged and/or with light purple veins.
subsp. uniflora
1. Calyx lobes ca. 2 times as long as tubes, subulate-triangular; corollas purple to blue (often with a white throat), yellow, or white, often with darker purple or blue veins.
subsp. occidentalis
1. Corollas 15–18(–22) mm, lips 3–6 mm, adaxial lips reflexed or revolute; anthers glabrous or tomentulose from pollen sacs, stalked glands often few on dorsal surfaces or absent; Chihuahuan Desert.
subsp. palmeri
1. Corollas (15–)18–32 mm, lips 5–10 mm, adaxial lips erect or reflexed; anthers glabrous, sparsely villous, or pubescent, stalked glands present on dorsal surfaces, sometimes obscure, rarely absent; Sonoran Desert and adjacent portions of California and Nevada.
→ 2
2. Corollas (15–)18–22 mm, adaxial lips erect, lobes with or without apiculate teeth.
subsp. cooperi
2. Corollas 22–32 mm, adaxial lips erect or reflexed, lobes with apiculate teeth.
subsp. latiloba
Source FNA vol. 17, p. 472. FNA vol. 17, p. 484.
Parent taxa Orobanchaceae > Orobanche Orobanchaceae > Orobanche
Sibling taxa
O. arizonica, O. bulbosa, O. californica, O. cooperi, O. corymbosa, O. fasciculata, O. ludoviciana, O. minor, O. multiflora, O. parishii, O. pinorum, O. ramosa, O. riparia, O. robbinsii, O. valida, O. vallicola
O. arizonica, O. bulbosa, O. californica, O. corymbosa, O. fasciculata, O. ludoviciana, O. minor, O. multiflora, O. parishii, O. pinorum, O. ramosa, O. riparia, O. robbinsii, O. uniflora, O. valida, O. vallicola
Subordinate taxa
O. uniflora subsp. occidentalis, O. uniflora subsp. uniflora
O. cooperi subsp. cooperi, O. cooperi subsp. latiloba, O. cooperi subsp. palmeri
Synonyms Anoplanthus uniflorus, Aphyllon uniflorum, Thalesia uniflora Aphyllon cooperi, Myzorrhiza cooperi, O. ludoviciana var. cooperi
Name authority Linnaeus: Sp. Pl. 2: 633. (1753) (A. Gray) A. Heller: Cat. N. Amer. Pl., 7. (1898)
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