76 KANSAS UNIVERSITY SCIENCE BULLETIN. 



since elongation of the egg and suspensor is always for the pur - 

 pose of removing the embryo from the sphere of haustorial 

 activity. In Lamium approximately half of the sac becomes 

 haustorium, and it is in view of this fact that the embryo is 

 transferred for development to the antipodal region. The 

 elongation of the suspensor in the majority of Labiatse exam- 

 ined appears to terminate its function, for disintegration fol- 

 lows. In Salvia, on the contrary, there is reason to believe that 

 it plays an important part in embryo nutrition. The cells com- 

 posing it are short and relatively rich in plasmatic contents. 



The first division of the endosperm nucleus results in the 

 formation of a cell at the extreme antipodal end of the embryo 

 sac. The wall cutting off this cell lies approximately in a plane 

 at right angles to the long axis of the embryo and suspensor. 

 The separating walls of cells produced in succeeding divisions 

 are at first parallel to the first wall. The embryo is soon sur- 

 rounded by endosperm tissue (fig. 16). One endosperm cell 

 takes a position near the end of the suspensor for the purpose 

 of entering directly into the formation of a haustorium. The 

 growth of the endosperm tissue surrounding the embryo is 

 greatest in a direction toward the upper part of the integument 

 and approximately parallel with the vascular bundle. As a re- 

 sult, an endosperm process, cylindrical in shape, projects into 

 the region where lies the most extensive portion of integument 

 tissue (fig. 17). The outgrowth is evidently designed to reach 

 the nutritive tissue remote from the main mass of endosperm. 

 Functionally, it is a haustorium, differing principally from 

 tissue-containing haustoria of certain other families of plants 

 in the greater number of cells. Figure 17 shows a young haus- 

 torium of Salvia lanceolata. In its maturer stages, seen dia- 

 grammatically in figure 19, it is composed of much elongated 

 cells. Such differentiation suggests conduction as a function. 

 The elongated cells lie principally in the axis of the haustorium 

 with their long axes parallel to that of the haustorium. The 

 peripheral cells serve as digestive and absorptive cells, while 

 those of the interior of the haustorium are conductive. The 

 products of its activity are transferred to the main mass of 

 endosperm which it thus serves as an absorbing organ. 



The other haustorium is coenocytic, and its activities are 

 directly concerned with embryo nutrition through the suspen- 

 sor. It is not a structure developed from the suspensor, though 



