OROBANCHACEAE. 331 



linear, usually wanting; calyx short, cup-shaped, the teeth very 

 variable; corolla swollen toward the base; upper lip entire or 

 notched; lower lip 3-parted; stamens slightly exserted; anther- 

 cells parallel, blunt at base; stigmas 2-lobed or 4-lobed; cap- 

 sules globose, 4-valved; seeds with a thin reticulated coat. 



Boschniakia hookeri Walp. (B. strobilacea Gray.) Tuber-like under- 

 ground stem globose, reticulated; stems stout, 10-30 cm. high, reddish, 

 flowering from near the ground; scale-like leaves rhomboidal, usually densely 

 imbricated, more or less erose; flowers sessile or nearly so; calyx very variable, 

 the teeth varying from subulate to broadly triangular, sometimes obsolete 

 or nearly so; corolla ciliate; filaments bearded at base; capsule globose; seeds 

 favose. 



From Vancouver Island, British Columbia, to California; first found by 

 Menzies at Nootka Sound. Northward the plant is parasitic on Gaultheria 

 shallon or rarely on Arctostaphylos ; southward the common host is Arctos- 

 taphylos but sometimes Arbutus menziesii. It seems impossible to maintain 

 B, hookeri, the northern plant, and the usually stouter southern form, B. 

 strobilacea, as distinct species. 



461. THALESIA. 



Yellowish, violet or nearly white herbs, parasitic on the roots of 

 various plants; scale-leaves scattered; flowers solitary or in 

 loose clusters; calyx 4- or 5-cleft; corolla 2-lipped, the upper lip 

 erect, mostly 2-lobed or emarginate, the lower spreading; stamens 

 included. 



Calyx-lobes subulate, longer than the tube. T. uniflora. 



Calyx-lobes triangular, shorter than the tube. T. fasciculata. 



Thalesia uniflora (L.) Britt. Stem stout, 1^1 cm. long, mostly sub- 

 terranean, with a few ovate obtuse scales and bearing 1-5 or more 1-flowered 

 glandular-puberulent peduncles 5-12 cm. high; calyx glandular, the obconic 

 or campanulate tube exceeded by the narrow subulate lobes; corolla violet or 

 yellowish, 1-2.5 cm. long, glandular-puberulent without. 



Rare in our limits. 



Thalesia fasciculata (Nutt.) Britt. Stems elongated, 2-12 cm. long, 

 bearing a cluster of 2-30 very glandular 1-flowered peduncles, 5-10 cm. high; 

 calyx-tube campanulate, about as long as the broad triangular lobes; corolla 

 yellowish, 1-2 cm. long. 



Parasitic on various plants; not common. 



462. OROBANCHE. 



Parasitic herbs on the roots of various plants, usually yellow- 

 ish or reddish; flowers in spikes, sessile or nearly so, with bracts; 

 calyx deeply 2-lobed, the lobes often 2-cleft; corolla irregular, the 

 tube slightly curved, the upper lip erect or incurved, the lower 

 spreading; capsule 2-valved. 



Flowers pedicellate; anthers woolly. 0. grayana. 



Flowers subsessile; anthers glabrous or nearly so. O. ludoviciana. 



