322 THE BROOMRAPE FAMILY. [Orobanche. 



It varies according to station, and the plant it affects. Many of these 

 varieties are considered as species, and three are commonly admitted 

 into the British Flora : O. picridis, F. Schultz, a tall, very pale : 

 coloured variety, growing on Picris hieracioides ; 0. amethystea, Thuill., 

 assuming a bluer tint than any of the others, and growing on Eryngium ; 

 0. Hederce, Duby, not uncommon on Ivy in the south of England and 

 Ireland, as on the Continent ; it is said to differ from the common 

 form in the yellow, not purple, stigma, and other trifling characters, 

 which, however, do not appear to be constant. 



6. O. ceerulea, VilL (fig. 723). Blue B. Stem simple or rarely 

 branched, 6 to 9 inches high, with a light bluish tint. Flowers of a 

 deep purplish-blue, with 2 small bracts at its base, 1 on each side, 

 besides the larger bract common to all Orobanches. Calyx usually 

 closed at the back by a fifth tooth or lobe, much shorter and broader 

 than the others. Corolla-lobe rather long and curved ; the 5 lobes, 

 although arranged in 2 lips, are less unequal, and less wavy than in 

 the preceding species. 



Chiefly, if not exclusively, on AchUlea MiUefolium ; not uncommon on 

 the continent of Europe, and in west-central Asia. In Britain, only in 

 grassy pastures near the sea, in the eastern and southern counties, and 

 in the Channel Islands. PL early summer. The 0. arenaria, Borkh., a 

 larger plant, of a paler blue, with hairy anthers, parasitical on Artemisia* 

 in light, sandy soils, has been found in Alderney. 



7. O. ramosa, Linn. (fig. 724). Branched B. Very much smaller 

 than 0. ceerulea, of a pale straw-colour, with smaller pale-blue flowers. 

 Stem often branched, seldom above 6 inches high. Flowers shaped 

 like those of 0. ccerulea, and, like them, they have 2 small lateral 

 bracts besides the larger one ; but the calyx is split at the back, and 

 has only 4 lobes, as in the brown Orobanches. 



On Hemp, Lucem, and some other crops, chiefly in southern Europe, 

 and has been found, though very rarely, in some of the southern and 

 eastern counties of England. Fl. summer. 



II. LATHRZEA. TOOTHWORT. 



A small genus closely allied to Orobanche, but the flowers are less 

 irregular, the calyx broadly campanulate or inflated, with 4 short, broad, 

 erect lobes, the upper lobe of the corolla forming a more or less distinct 

 upper lip, and the 4 placentas to which the seeds are attached in the 

 capsule are more fleshy, and more distinctly united in pairs. 



1. Ij. squamaria, Linn. (fig. 725). Common T. A pale rose-coloured 

 plant, with flesh-coloured or slightly bluish flowers, streaked with purple 

 or dark red. Rootstock fleshy and creeping, covered with close-set, 

 short, thick, fleshy scales. Flowering stems erect, from 3 or 4 inches 

 to near a foot high, with a few broad, orbicular, much less fleshy scales, 

 passing gradually into the bracts. Flowers numerous and nodding, in 

 a dense spike, or sometimes shortly stalked. Calyx about 6 lines long. 

 Corolla half as long again, the upper lip entire or slightly notched. 

 Stamens and style nearly as long as the corolla, or sometimes, especially 

 the style, projecting beyond it. 



On the roots of trees, especially the Hazel, throughout Europe and 



