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cancer- or squaw-root, cancer-root

American cancer-root, American squaw-root, bear corn, conopholis d'amérique, squawroot

Habit Herbs, perennial; achlorophyllous, holoparasitic, with perennial, tuberlike underground vegetative structure attached to host root, dark brown or black, with a sclerenchymatous, knobby surface, roots absent.
Stems

erect, yellow, brown, or black, fleshy, glabrous.

6–20 cm.

Leaves

cauline, spiral, tightly imbricate;

petiole absent;

blade stiffly chartaceous, margins entire or minutely erose or ciliate.

triangular to broadly lanceolate, 5.5–18 × 5–12 mm, glabrous or minutely hairy along margins.

Bracts

mostly concealing calyces, lanceolate, 5–18 × 2–8 mm, margins entire or minutely erose, not ciliate, glabrous, veins visible or obscure.

Inflorescences

terminal, compact racemes;

bracts present.

Pedicels

present;

bracteoles present, sometimes absent.

0–4(–6) mm;

bracteoles 2.

Flowers

sepals 2, 4, or 5, calyx bilaterally symmetric, tubular, divided abaxially, not divided adaxially, lobes lanceolate;

petals 5, corolla yellow, strongly bilabiate, tubular, arching forward, abaxial lobes [1–]3, adaxial 2, adaxial lip notched;

stamens 4, didynamous, exserted, filaments glabrous or hairy at base;

staminode 0;

ovary 1-locular, placentation parietal;

stigma disciform-crateriform or 2–4-lobed.

calyx 3–8 mm, lobe margins entire or erose, not ciliate, apex acute;

corolla 8–14 mm;

anthers glabrous.

Capsules

indehiscent.

5–15 × 5–12 mm;

styles persistent.

Seeds

300–600, glossy tan, brown, or black, irregularly ellipsoid or angled, wings absent.

Conopholis

Conopholis americana

Phenology Flowering Feb–Jun.
Habitat Under oaks in moist deciduous or mixed deciduous-coniferous woods.
Elevation 30–600 m. (100–2000 ft.)
Distribution
from USDA
e North America; Mexico; Central America; sw North America
[BONAP county map]
from FNA
AL; CT; DC; DE; FL; GA; IL; IN; KY; MA; MD; ME; MI; NC; NH; NJ; NY; OH; PA; RI; SC; TN; VA; VT; WI; WV; MB; NS; ON; QC; s Mexico
[WildflowerSearch map]
[BONAP county map]
Discussion

Species 3 (2 in the flora).

Five species have been described in the genus; most authors accept Conopholis as including only from one to three species (R. R. Haynes 1971; A. G. Rodrigues et al. 2011, 2013). All taxa in the genus are strikingly similar morphologically. Differences in scale leaves, floral bracts, flowers, vestiture, and plant size have been used to separate species and varieties; the variability of these characters within taxa occasionally exceeds between-taxon differences. There is considerable overlap in any character set used to separate taxa. J. W. Thieret (1971) suggested that all taxa could be considered conspecific. Molecular and morphological studies by Rodrigues et al. (2011, 2013) provided strong evidence that three species should be recognized. The third taxon, C. panamensis Woodson, is known only from Central America. Hosts are all members of Quercus (Fagaceae).

Conopholis fruits develop a woody texture at maturity. Although members of the family are generally stated to produce capsular fruits, those of Conopholis generally remain indehiscent until degraded by either physical abrasion or invasion by predatory insects, such as ants. Seed dispersal tends to be of two types: short-range dispersal by the action of gravity, wind, and/or water following the breach of the wall; and longer-range dispersal following ingestion of the plants by various mammals.

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

A. G. Rodrigues et al. (2013) noted the existence of a single historical specimen from Jeff Davis County, Texas, and suggested that this represented a historical disjunction. However, it is also possible that the specimen in question was mislabeled.

V. Baird and J. L. Riopel (1986) documented the dispersal of Conopholis americana in the eastern United States by deer and rodents.

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

Key
1. Bracts glabrous, lanceolate, mostly concealing calyces, margins entire or minutely erose, not ciliate; leaves glabrous or minutely hairy along margins, triangular to broadly lanceolate; calyces 3–8 mm, lobe apices acute; corollas 8–14 mm; anthers glabrous.
C. americana
1. Bracts glandular-pubescent, narrowly lanceolate, mostly not concealing calyces, margins entire, glandular-ciliate; leaves mostly glandular-pubescent, triangular to narrowly lanceolate; calyces 6–9 mm, lobe apices obtuse; corollas 14–20 mm; anthers sparsely pilose or glabrous.
C. alpina
Source FNA vol. 17, p. 461. Authors: L. Turner Collins, Alison E. L. Colwell, George Yatskievych. FNA vol. 17, p. 462.
Parent taxa Orobanchaceae Orobanchaceae > Conopholis
Sibling taxa
C. alpina
Subordinate taxa
C. alpina, C. americana
Synonyms Orobanche americana
Name authority Wallroth: Orobanches Gen. Diask., 78. (1825) (Linnaeus) Wallroth: Orobanches Gen. Diask., 78. (1825)
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