170 Boeshore — The Morphological Continuity of 



In Gerardia, the seeds are numerous, oblong wedge-shaped 

 or angular; the testa is loose-fitting. 



In Euphrasia, the numerous seeds are pendulous, oblong, 

 with longitudinal ridges. 



In Bartsia, the seeds are many, pendulous, or may be numer- 

 ous and placed subtransversely, with wings and longitudinal 

 ridges. 



In Tozzia, the seeds are ovoid-globose; the testa is appressed; 

 and the embryo is small. 



The seeds of Buchnera are very numerous and ovoid or oblong; 

 the testa is reticulate, subappressed. 



In Harveya, the seeds are very numerous; the testa is heavily 

 reticulated and loose; the embryo is equal to half the albumen in 

 amount. 



In Hyobanche, the seeds are numerous, small, globose; the 

 testa is loose, reticulated. 



Lathraea has numerous small seeds, spherical in shape, and 

 the testa is wrinkled. 



In species of Orobanche, the seeds are numerous, reticulated, 

 wrinkled or striate; the embryo is minute with cotyledons scarce- 

 ly differentiated. 



In Christisonia, the seeds are extremely numerous, very small, 

 and subglobose, and the testa is reticulated. 



In Aphyllon, the seeds are numerous, small, light, surrounded 

 by a tough leathery coat of flattened cells with thick indurated 

 walls; the endosperm cells are filled with starch and enclose a 

 small embryo consisting of a group of undifferentiated cells. 



In Conopholis, the seeds are of fair size, numerous, and some- 

 what quadrangular in shape; the embryo is small, undifferent- 

 iated; and the testa is heavily thickened. 

 t In Epiphegus, the seeds are very numerous (from 700 to 1800) 

 small, oblong in shape; the embryo is a group of undifferentiated 

 cells; and the testa cells are elongated with much thickened 

 walls. 



Selection of Hosts 



The less parasitic Scrophulariaceae have a rather wide range 

 of hosts. The species of Gerardia parasitize on Grasses, Com- 

 posites, etc., as has already been stated. 



For Bartsia, the following are given as hosts: Avena flaves- 

 cens, Phleum pratense, Trifolium pratense. 



