69G Rydberg : Rocky Mountain flora 



Myzorrhiza xanthochroa (Nels. & Cockerell) Rydb. comb. nov. 

 Orobanche xanthochroa Nels. & Cockerell, Bot. Gaz. 37 : 278. 

 1904. 



Myzorrhiza corymbosa sp. nov. 



Stem 5-10 cm. high, corymbosely branched, glandular-puber- 

 ulent ; scales about I cm. long, lance-ovate, acute ; bracts linear, 

 about 1 cm. long; pedicels 5-10 mm. long; bractlets linear-subu- 

 late, half as long as the calyx ; calyx-tube obconic, glandular- 

 puberulent, 4 mm. long ; lobes lance-subulate, about 1 cm. long ; 

 corolla dark purple, about 2.5 cm. long, tube 4-5 mm. wide; 

 upper lip 7-8 mm. long, cleft about one third its length into 

 ovate, obtuse or sometimes retuse lobes ; lower lip cleft to the base 

 into three lanceolate acutish divisions ; anthers woolly. 



This species has been confused with M. calif ornica and M. 

 ludoviciana, but is evidently most nearly related to M. Grayana 

 {Orobanche comosa Hook.). In Hooker's Flora, the latter is de- 

 scribed and figured as having emarginate corolla lobes. I doubt 

 if that is a constant character. There is a fragment of Hooker's 

 type in the Torrey herbarium ; some of the lobes are evidently so, 

 but in others this character is rather obscure. Good specimens, 

 collected by Dr. Cooper on the Stevens' Expedition and also pre- 

 served in the Torrey herbarium, and a colored drawing, made for 

 the report of the Wilkes' Expedition but never published, illus- 

 trate a plant with the lobes of the lower lip lanceolate, acute and 

 entire at the apex. These and the specimen received from Hooker 

 agree otherwise wholly in habit, size, structure, and color of the 

 corolla. Whether the notching of the lower lobes is a specific 

 character or not, may be decided by further field study. It is 

 evident that the specimens cited here below are distinct enough 

 from both. Hooker's and Cooper's plants have a corolla fully 

 3 cm. long, light purple and of a thinner texture, the lips are 12-15 

 mm. long, i. e., about twice as long as in the plant here described, 

 the upper lip is cleft to about the middle and the lobes of the lower 

 lip are relatively narrower. The corolla of M. corymbosa resembles 

 more in form, size, texture, and color that of M. ludoviciana, 

 although the upper lip is less deeply 2-cleft. Occasionally one 

 finds stunted specimens of M. ludoviciana, which in habit resem- 

 ble this, but they can easily be recognized by the shorter calyx- 



