1915] MICHELL—STRIGA LUTEA 131 
solaneae, Antirrhineae, and Rhinanthoideae. It is on this last 
group that most work has been done, though its subdivision 
Rhinanthoideae-Gerardieae, to which Striga belongs, has up to the 
present not been investigated. For this reason it is of great 
interest to discover how far Striga may be compared with the 
plants belonging to the Rhinanthoideae-Digitaleae and Rhinan- 
thoideae-Rhinantheae. In all the plants which have been studied 
the features of the greatest interest are found in the post-fertilization 
phases of development and in this respect Siriga lutea is no 
exception. 
“Double fertilization”? has been demonstrated in Linaria vul- 
garis, Digitalis purpurea, Pedicularis foliosa, and Melampyrum 
silvaticum, to which may now be added Siriga luiea. 
The development of haustoria and the development of endo- 
sperm go hand in hand and therefore may be treated together. 
ScHMID (13) puts the genera he has studied into four groups ac- 
cording to their method of endosperm formation. 
In the first he puts Verbascum, Scrophularia, and Digitalis. In 
these genera four superposed primary endosperm cells are formed, 
of which only the two inner ones form the true endosperm, the 
uppermost and lowermost cells dividing into four and assuming a 
haustorial function, though in a much less marked inset ner 
than is found in the other groups. : 
Linaria and Antirrhinum constitute a second group. In them 
a transverse division of the embryo sac occurs. The upper cell 
gives rise to the endosperm, of which a few cells at the micropylar 
end function as a haustorium; the lower cell grows out into a tube- ° 
like haustorium, in which no cell walls are formed though the 
original nucleus divides once. 
The third group contains Alectorolophus (Rhinanthus) and part 
of the genus Lathraea, which Scum includes in the Scrophularia- 
ceae. Here, as in the second group, the lower cell becomes a 
haustorium without septation, and two cells arising at the micro- 
pylar end of the upper cell give rise to a micropylar haustorium. 
Each of these cells has two nuclei. 
Veronica, Euphrasia, Pedicularis, Melampyrum, and Toszzia are 
put in the fourth group, which differs from the third only in that 
