694 Rydberg : Rocky Mountain flora 



The typical OrobancJie has the calyx characteristic of, for instance, 

 Castilleja in Scrophulariaceae, i. c, the calyx is deeply cleft in 

 front and behind, with the lateral divisions entire or 2-cleft. None 

 of our native American plants has this structure. They have all 

 (except those included in Boschniakia by Gray) an almost equally 

 5-toothed calyx. There is a group of Old World plants, of which 

 Orobanche purpurea and 0. ramosa are introduced into this country, 

 which have a 4-toothed or only occasionally 5-toothed calyx, but 

 in that case the upper tooth is much smaller. In Gray's New 

 Manual the former is described as having a " 5-lobed " calyx. 

 This is only occasionally the case. These species constitute the 

 genus Kopsia Dum. or Phelipaea Nees (not Desf.). The writer 

 thinks that the five sections of Beck's monograph should be re- 

 garded as genera. Myzorrhiza Philippi is the only available name 

 for Aphyllon § Nothaphyllon Gray. This genus differs from Tlialesia 

 in habit and in the arrangement of the placentae, from Crobanche in 

 the regularly 5-toothed instead of 2-cleft calyx, and from both in 

 the presence of bractlets. The type ot th 1 genus is 



Myzorrhiza chilensis Philippi^ Linnaea 29: 36. 1857 

 Orobanche chilensis G. Beck, Bibl. Bot. 4 : 82. 1890. 

 This is closely related to our most common North American 

 species : 



Myzorrhiza ludoviciana (Nutt.) Rydb.; Small, Fl. SE. U. S. 



1093. 1903 

 OrobancJie ludoviciana Nutt. Gen. 2: 58. 18 18. 

 Phelipaea ludoviciana Walp. Rep. 3: 461. 1844. 

 Aphyllon ludovicianum A. Gray, Bot. Calif. I : 585. 1876. 

 ? Aphyllon arenosum Suksd. Allg. Bot. Zeits. 12 : 27. 1906. 



given for the two first are correct ; there are three scales under the flower, one bract 

 and two lateral bractlets ; Orobanche minor has one bract and no bractlets, while O. 

 ludoviciana has i or 2 bractlets under the flower. It has exactly the same arrangement 

 as O. purpurea and O. ramosa, except that one of the bractlets is sometimes lacking 

 and the bract is usually some distance below the calyx. Orobanche uniflora and O. 

 fasciculate are not without bracts. They are without bractlets, but the bract is found at 

 the base of the longer pedicel. They are like O. minor (a typical Orobanche) in hav- 

 ing no bractlets, but differ in the 5-toothed instead of 2-cleft calyx. O. ludoviciana 

 has bractlets and should have been associated with the two first species, if the presence 

 or absence of bractlets was taken as the dividing character. In all the species the 

 bracts are present although situated at different distances from the calyx, depending 

 upon the length of the pedicels. 



