Orobanche ludoviciana |
Orobanche corymbosa |
|||||
---|---|---|---|---|---|---|
Louisiana broomrape |
flat-top broomrape |
|||||
Habit | Plants simple or few-branched, 7–40(–54) cm, usually stout, base enlarged in robust specimens. | Plants simple, rarely branched, 5–12(–18) cm, usually slender, base sometimes enlarged. | ||||
Roots | inconspicuous to conspicuous (often forming an amorphous mass), slender, usually branched. |
usually inconspicuous (sometimes forming an irregular mass), slender, unbranched or with short bifurcations. |
||||
Leaves | several to numerous, appressed; blade lanceolate to lanceolate-ovate, 5–10 mm, margins entire, apex acute, surfaces sometimes glandular-pubescent. |
few to several, appressed; blade broadly lanceolate or ovate, 5–10 mm, margins entire or slightly erose, apex acute or obtuse, surfaces often glandular-pubescent. |
||||
Inflorescences | spikelike racemes, purple, lavender, or pallid distally, rarely yellow, sometimes branched, glandular-pubescent; flowers numerous; bracts ± reflexed, lanceolate, 8–12 mm, apex acute or attenuate, densely glandular-pubescent. |
racemelike to elongate corymbs or short racemes (sometimes corymbose), rose, pink, purple, or white, simple, densely glandular-pubescent; flowers numerous (rarely 10 or fewer in depauperate plants); bracts slightly reflexed, narrowly lanceolate or almost linear, 7–11 mm, apex acute, glandular-pubescent. |
||||
Pedicels | 0–15 mm, much shorter than plant axis; bracteoles 2. |
3–20 mm proximally, 0 mm distally, shorter than plant axis; bracteoles 2. |
||||
Flowers | calyx purple, lavender, or pallid, weakly bilaterally symmetric, 8–14 mm, deeply divided into 5 lobes, lobes lanceolate-subulate, glandular-pubescent; corolla 14–20 mm, tube white to pallid or cream, sometimes pinkish or light purplish tinged distally, sometimes with purple veins, constricted above ovary, slightly curved forward, glandular-pubescent; palatal folds prominent, yellow, pubescent; lips externally white to pallid or cream, sometimes pinkish or light purplish tinged, internally pink or purple, sometimes white with purple veins, rarely light yellow, abaxial lip spreading, 3–5 mm, lobes oblong-lanceolate, apex obtuse or rounded, adaxial lip erect or slightly reflexed, 4–6 mm, lobes ovate, sometimes deltate, apex rounded or obtuse to bluntly pointed; filaments glabrous or pilose at base, anthers included or slightly exserted, glabrous or with few woolly hairs along sutures. |
calyx lavender, pink, white, or yellow, sometimes burgundy, ± radially symmetric, 12–24 mm, deeply divided into 5 subequal (reflexed or contorted) lobes, lobes linear-subulate, densely glandular-pubescent; corolla (15–)18–34 mm, tube white to grayish white, pale pink to pink, or pale purple to purple, rarely brick red, sometimes with darker pink to purple veins, slightly constricted above ovary, bent forward, glandular-pubescent or glabrate; palatal folds prominent, yellow, glabrous (with blisterlike swellings); lips white to ± pink, pale purple to purple, brick red, or pinkish red, sometimes with darker pink to purple veins or internally darker, abaxial lip spreading, 5–9 mm, lobes oblong to oblong-lanceolate, apex acute or rounded, adaxial lip erect or reflexed, 5–9 mm, lobes oblong, apex rounded, truncate, or emarginate, rarely acute; filaments glabrous, anthers included, tomentose, sometimes glabrous (subsp. mutabilis). |
||||
Capsules | ovoid, 6–13 mm. |
ovoid to oblong-ovoid, 5–13 mm. |
||||
Seeds | 0.3–0.5 mm. |
0.3–0.5 mm. |
||||
2n | = 48. |
|||||
Orobanche ludoviciana |
Orobanche corymbosa |
|||||
Phenology | Flowering Apr–Aug. | |||||
Habitat | Prairies, sand hills, sand dunes, eroded ground, glades, roadsides. | |||||
Elevation | 0–2500 m. (0–8200 ft.) | |||||
Distribution |
CO; ID; IL; KS; MN; MO; MT; ND; NE; NM; OK; SD; TX; WA; WI; WY; AB; BC; MB; SK
|
AZ; CA; ID; MT; NM; NV; OR; UT; WA; WY; AB; BC; MB
|
||||
Discussion | Orobanche ludoviciana is one of the most widely distributed species of Orobanche in North America. It commonly occurs in wind and water eroded habitats, principally in the Great Plains of North America and contiguous areas. Throughout most of its range, Orobanche ludoviciana parasitizes Grindelia squarrosa and several species of Artemisia. However, at the southern limits of the range in Texas, it has been reported on Baccharis, Haploësthes, Heterotheca, and Thelesperma (Asteraceae); in Canada, Heterotheca villosa is an important host. The reports on cultivated crops (tomato and tobacco) are the result of misidentifications by P. A. Munz (1930) and should be attributed to O. cooperi and O. riparia. The binomial Orobanche ludoviciana has often been broadly applied to several taxa in western states, including several taxa treated herein as species. P. A. Munz (1930) inadvertently used a specimen of Orobanche riparia to describe and illustrate the corollas of O. ludoviciana as having pointed corolla lobes. This led him to include several western taxa that have pointed corolla lobes within O. ludoviciana, including taxa treated here as species: O. cooperi, O. riparia, and O. valida. L. T. Collins et al. (2009) clarified this issue, pointing out that the corolla lobes are in fact rounded. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Subspecies 2 (2 in the flora). The range of Orobanche corymbosa includes the Great Basin Desert, Intermountain Region, Columbia Plateau, and contiguous areas. The two subspecies are sympatric through most of the geographic range of the species. Areas of sympatry exist with several other species of Orobanche: in the west with O. californica; in the north and east with O. ludoviciana; and in the south with O. arizonica and O. multiflora. Subspecies mutabilis tends to produce more racemose inflorescences, while subsp. corymbosa typically produces more compact corymbose inflorescences. This suggests a genetic affinity between O. corymbosa and members of the O. californica and O. ludoviciana groups. The southern members of subsp. corymbosa in California and Nevada appear to intergrade with O. californica across the Sierra Nevada. However, there are exceptional individuals in every population, so seasonal weather may cause variations in plant morphology. Inflorescence differences could also be associated with the ploidy differences reported in Orobanche corymbosa (L. R. Heckard and T. I. Chuang 1975). Ploidy and morphological instability may indicate significant introgression or a hybrid origin of O. corymbosa. Both subspecies share a somewhat ampliate corolla tube, which is a good field character for this species when compared with species with which it has an overlapping range. Orobanche corymbosa is parasitic on species of Artemisia (Asteraceae), principally A. tridentata, but has occasionally been reported on Iva (Asteraceae) and Atriplex and Sarcobatus (Chenopodiaceae). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
||||
Key |
|
|||||
Source | FNA vol. 17, p. 481. | FNA vol. 17, p. 476. | ||||
Parent taxa | ||||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Aphyllon ludovicianum, Myzorrhiza ludoviciana, O. ludoviciana var. arenosa, O. multiflora var. arenosa | Myzorrhiza corymbosa, Aphyllon corymbosum, O. californica var. corymbosa | ||||
Name authority | Nuttall: Gen. N. Amer. Pl. 2: 58. (1818) | (Rydberg) Ferris: Contr. Dudley Herb. 5: 99. (1958) | ||||
Web links |
|