Scrophulariaceae and Orobanchaceae 161 



the less parasitic forms, but as these intervening vegetative axes 

 become shortened and increasingly degraded in the more par- 

 asitic forms like Harveya and Hyobanche the flowering stalks 

 gradually approach a lower level until they take their origin 

 only a few inches from the ground. The conspicuous part of 

 the plant then consists of the short vegetative axis and the floral 

 axis. In the Orobanchaceae with the greatly reduced stems the 

 flowering axes constitute almost wholly the aerial parts of the 

 plant. In the former the flowering axes are woody, while in 

 the latter they are more or less fleshy and stout, with one excep- 

 tion (Aphyllon). 



The type of inflorescence for the Scrophulariaceae is given 

 by systematists as centripetal, racemose. Gerardia flava has 

 one floral axis along which short-pedicelled flowers are arranged 

 racemosely. In G. purpurea, G. aspera, G. aphylla and 

 others there are several floral axes, each of which constitutes a 

 raceme; the pedicels are of varying lengths. In some of the 

 more parasitic forms the branching of the flower stalk is less fre- 

 quent and the flowers have very short pedicels so that the type 

 of inflorescence tends to become a loose spike, e. g. Orthocarpus 

 purpurea, Euphrasia, Bartsia viscosa, Odontites, Hyobanche, etc. 



Aphyllon has one floral axis bearing a terminal flower. Epip- 

 hegus has branched flowering stalks and the flowers are ar- 

 ranged racemosely or in a spike. In the other genera, Lath- 

 raea, Orobanche, and Conopholis, of the Orobanchaceae the 

 flowers are arranged in a dense spike. 



The bracts of the flowers in Scrophulariaceae are leaf -like 

 becoming scale-like, or even scales in Hyobanche while in Oro- 

 banchaceae they are scales. 



Comparative Study of the Flower 



Calyx. 



The calyx in the different genera studied shows considerable 

 variation in the number of sepals, in form, and in hairs. 



In species of Pedicularis the calyx may be in the form of a 

 funnel, or bell-shaped with from 2 to 5 teeth at the top. The 

 teeth may be simple or further toothed or lobed. 



The calyx of Melampyrum lineare is comparatively small and 

 is made up of a short tube below and 4 tapering teeth above, the 



