OROBA JVC// A CEA E. 849 



1. THALLSIA Raf. [APHYLLON A.Gray.] 



Glandular or viscid-pubescent simple-stemmed herbs, parasitic on the roots of 

 various plants, with scattered scales, and long-peduncled flowers. Calyx campanu- 

 late or hemispheric, the lobes acute or acuminate. Corolla-tube elongated, curved, 

 the limb slightly 2-lipped. the upper lip erect- spreading, 2-lobed, the lower spread- 

 ing, 3-lobed, the lobes all nearly equal. Stamens included; anther-sacs mucronate 

 at the base. Ovary ovoid; style slender, deciduous; stigma peltate, or transverse- 

 ly 2-lamellate. [Dedicated to Thales.] About 3 species, of N. Am. 



Stem very short ; peduncles 1-4, erect ; calyx-lobes lanceolate, acuminate. 



1. T. uniflora. 

 Stem erect, 5-13 cm. high; peduncles several; calyx-lobes broad, acute. 



2. T. fasciculata, 



1. Thalesia uniflora (L.) Britton. Pale or Naked Broom-rape. One- 

 flowered Broom-rape. Cancer-root. (I. F. f. 3358.) Stem usually less 

 than 2.5 cm. long, nearly subterranean, bearing several ovate-oblong scales and 

 1-4 erect scape-like glandular-puberulent i-flowered peduncles, 7-20 cm. high. 

 Cahx campanulate, pubescent, glandular. 8-10 mm. high, less than one-half the 

 length of the corolla, its lobes as long as the tube or longer, lanceolate, acuminate; 

 corolla white or violet, puberulent without, 1.5-2.5 cm. long, the tube about 3 

 times as long as the limb, the short lobes oval or obovate, obtuse; placentae nearly 

 equidistant; capsule ovoid, longer than the calyx. In woods and thickets, Newf. 

 to Br. Col., Va., Ohio, Tex. and Cal. April-June. 



2. Thalesia fasciculata (Nutt.) Britton. Clustered or Yellow Cancer- 

 root. (I. F. f. 3359-) Stem densely glandular-pubescent, bearing several scales 

 and 3-15 naked i-flowered peduncles 2-8 cm. long. Calyx glandular, broadly 

 campanulate, 6-10 mm. high, about one-third the length of the corolla, its 

 lobes triangular-lanceolate or triangular-ovate, acute, equalling or shorter than the 

 tube; corolla nearly 2.5 cm. long, purplish yellow, puberulent without, the tube 

 3 times as long as the limb, the lobes oblong, obtuse, the limb more manifestly 

 2-lipped than in the preceding species; capsule ovoid to globose. In sandy soil, 

 Ind. to the N. W. Terr., Br. Col., Neb., Ariz, and Cal. April-Aug. 



Thalesia fasciculata liitea (Parry) Britton. Whole plant light yellow. Western 

 Neb. and Wyo. 



a. OROBANCHE L. 



Glandular-pubescent herbs, parasitic on the roots of various plants, with scat- 

 tered scales, and spicate or racemose, bracted and sometimes bracteolate flowers. 

 Calyx split both above and below, nearly or quite to the base, the divisions 2 -cleft 

 or rarely entire, or unequally 2-5-toothed. Corolla oblique, strongly 2-lipped; 

 upper lip erect, emarginate or 2-lobed; lower lip spreading, 3-lobed. Stamens 

 included; anther-sacs mostly mucronate at the base. Style slender, commonly 

 persistent until after the dehiscence of the capsule; stigma peltate to funnelform, 

 entire, or laterally 2-lamellate. [Greek, Choke-vetch.] About 90 species, of the 

 Old World and western Am. Besides the following, some 6 others occur in western 

 N. Am. 



Calyx 4-toothed; stems mostly branched. 1. O. ramosa. 



Calyx split on both sides: stem simple. 2. O. minor. 



Calyx 5-cleft; stem simple. 3. O. Ludoviciana. 



i. Orobanche ramdsa L. Hemp or Branched Broom-rape. (I. F. f. 

 3360.) Plant yellowish; stem branched, or rarely simple, 0.7-4 dm. high, the 

 scales few and distant. 4-10 mm. long. Spike loosely many-flowered, denser 

 above than below, the lowest flowers short- pedicelled; bracts usually 3, the longest 

 about equalling the calyx; calyx- teeth triangular-ovate, acute, or acuminate, about 

 as long as the tube; corolla 1-2 cm. long, the tube yellow, slightly constricted 

 above the ovary, the limb bluish. Parasitic on the roots of hemp and tobacco, Ky. 

 Adventive or nat. from Europe. Summer. 



2. Orobanche minor J. E. Smith. Lesser or Clover Broom-rape. Herb- 

 bane. (I. F. f. 3361.) Plant yellowish-brown; stem 1-5 dm. high; lower scales 

 numerous, ovate-oblong, the upper lanceolate, acute, scattered, 6-20 mm. long. 



