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

cluster 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 branched proximally and/or distally, rarely simple, 6–25(–35) cm (including pedicels), stem portion 1.5–15(–22) cm, slender to moderately stout, base slightly enlarged.
Roots

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

inconspicuous, slender or stout, unbranched or few-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.

few to several, erect or reflexed;

blade oblong-ovate to ovate-triangular or awl-shaped, (4–)6–12(–15) mm, margins entire, apex acute or acuminate, surfaces glandular-pubescent distally.

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.

fascicles, irregular corymbs, or short racemes of (1–)6–15(–20) flowers at stem or branch tips, light yellow to yellow or tinged pinkish to reddish purple, simple, densely glandular-pubescent, sometimes glabrescent proximally;

bracts erect or ± spreading, oblanceolate to oblong, lanceolate, or awl-shaped, sometimes ovate, 7–12 mm, apex acute, sometimes acuminate, moderately to densely glandular-pubescent.

Pedicels

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

bracteoles 0.

10–70(–150) mm, proximal as long as or ± longer than plant axis, distal sometimes shorter;

bracteoles 0.

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 light yellow to orangish yellow, tan, or grayish tan, often purplish tinged distally, sometimes entirely pinkish purple to reddish purple or dark purple, ± radially symmetric, (4–)6–12(–18) mm, divided into 5 subequal lobes, lobes shorter than to slightly longer than tube, triangular to subulate-triangular, moderately to densely glandular-pubescent;

corolla (11–)14–30(–38) mm, tube white to cream or yellow, purplish tinged, or pinkish purple to reddish purple, sometimes with darker pink, purple, or brown veins, slightly to moderately constricted above ovary, ± bent forward, glabrate or glandular-pubescent;

palatal folds ± prominent, usually yellow, moderately to densely glandular-pubescent;

lips yellow or pinkish purple to reddish purple, rarely white, sometimes with darker purple veins, abaxial lip ± spreading, 3–6(–9) mm, lobes oblong-obovate to nearly round, sometimes oblong-elliptic, apex rounded or ± pointed, sometimes shallowly emarginate, adaxial lip slightly to moderately spreading or recurved, (2–)3–6(–9) mm, lobes oblong-ovate to nearly round, sometimes oblong-elliptic, apex rounded or ± pointed;

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

Capsules

ovoid to oblong-ovoid, 4–8(–11) mm.

ovoid to oblong-ovoid, 6–12 mm.

Seeds

0.1–0.4 mm.

0.2–0.5 mm.

2n

= 48.

Orobanche uniflora

Orobanche fasciculata

Phenology Flowering Apr–Aug.
Habitat Sagebrush, chaparral, upland prairies, dunes, desert scrub, rocky slopes, hardwood and coniferous woodlands and forests, thickets, alpine meadows, roadsides, gardens.
Elevation 150–3300 m. (500–10800 ft.)
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
AK; AZ; CA; CO; IA; ID; IL; IN; KS; MI; MN; MT; ND; NE; NM; NV; OK; OR; SD; TX; UT; WA; WI; WY; AB; BC; MB; ON; SK; YT; Mexico (Baja California, Chihuahua)
[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.)

Similar to Orobanche uniflora, O. fasciculata forms a polymorphic complex that may involve cryptic species. However, unlike O. uniflora, infraspecific taxa in O. fasciculata lack strong correlations with morphology, geography, and host ranges; they are not recognized here. Previously, D. M. Achey (1933) separated the species into three varieties based mainly on plant color and flower size. In her unpublished thesis, K. C. Watson (1975) expanded this to four subspecies but circumscribed her taxa differently. Both authors noted morphological overlap among taxa.

Of particular interest is a series of populations from California and adjacent Oregon [always parasitic on Galium (Rubiaceae)] to which Watson applied the manuscript name "subsp. uniflorioides" and that, in many ways, are morphologically intermediate between Orobanche fasciculata and O. uniflora. Recently, A. E. L. Colwell et al. (2017) segregated these under the name Aphyllon epigalium Colwell & A. C. Schneider. They are distinctive in having typically two to four flowers per stem, usually cream to yellow corollas (sometimes tinged with pink or purple), including the palatal folds, and glandular (versus ciliolate) corolla margins. Colwell et al. went further in subdividing their new species into two subspecies, segregating plants with somewhat smaller, cream-colored corollas having at most slightly recurved lips as subsp. notocalifornicum A. C. Schneider & Colwell and retaining plants with somewhat larger, yellow corollas with spreading lobes as subsp. epigalium. This treatment is tentative, pending further research into the population genetics within the entire complex.

Most references suggest that Orobanche fasciculata uses a broad range of hosts. However, there are four main genera of host plants: Artemisia (Asteraceae), Phacelia (Hydrophyllaceae), Eriodictyon (Namaceae), and Eriogonum (Polygonaceae). As noted above, a morphologically distinctive set of populations parasitizes Galium. Other less commonly reported hosts include Ericameria and Eriophyllum (Asteraceae), Atriplex and Grayia (Chenopodiaceae), Convolvulus (Convolvulaceae), Arctostaphylos (Ericaceae), Mirabilis (Nyctaginaceae), Pinus (Pinaceae), grasses (Poaceae), Delphinium (Ranunculaceae), Adenostoma, Prunus, and Purshia (Rosaceae), and Vitis (Vitaceae). Some minor hosts are listed based only on specimen label data and require confirmation.

(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
Source FNA vol. 17, p. 472. FNA vol. 17, p. 474.
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. cooperi, O. corymbosa, 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
Synonyms Anoplanthus uniflorus, Aphyllon uniflorum, Thalesia uniflora Anoplanthus fasciculatus, Anoplon fasciculatus, Aphyllon fasciculatum, O. fasciculata var. franciscana, O. fasciculatum var. lutea, O. fasciculata var. subulata, Phelypaea fasciculata, Thalesia fasciculata
Name authority Linnaeus: Sp. Pl. 2: 633. (1753) Nuttall: Gen. N. Amer. Pl. 2: 59. (1818)
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