YAMPOL.SKY: Siiidy o f OU palm. 159 



tlie cells. At first thèse spaces are small, but wheii the cells take on a 

 stellate cliaracter tliey become considerably larger. The cells furthest away 

 from tlie end of the haiistorium are tlie largest. With the emerg'ence of the 

 cotylédon from the germ pore the constriction between the haustorium and 

 the cotylédon becomes more proiiounced and the epidermal cells of the 

 haustorium, which in the resting stage are not sharply separated from the 

 epidermis of the cotylédon, become so now. In Figure 128 whicli is a 

 longitudinal section of an haustorium in a very early stage of germination 

 ail the above mentioned régions can be made out with but little difficulty. 

 It is also to be noted that the bundies make a distinct zone of division 

 between the spongey parenchyma and the most active meristematic région. 

 The vascular system of the haustorium is always peripheral, no vascular 

 éléments ever pass into the spongey parenchyma. 



If we examine the lobes in an early stage of germination we find that 

 there is no spongey tissue élément there and we also find that they are 

 the seat of very active cell division. 



The cells of the epidermis through their active division keep on adding 

 more cells, keeping pace with the division in the interior of the haustorium. 

 The cells inside of the epidermis divide to form the tissue of the bundies 

 which enter the new lobes of the haustorium, and also the cells that form 

 the spongey pareiichyma of the growing organ. 



The subséquent development of the haustorium is primarily an extension 

 of the organ in ail directions without entailing any profound modifications 

 of the tissue. Lobes increase in number. Figure 12Q, Plate XVi, is a 

 somewhat older stage than the one shown in Figure 128. The sides of 

 the longitudinal section show the characteristic lobing. In a cross section 

 of a still later stage (Figure 130) the lobes hâve increased in number. Into 

 each lobe one or two branches from a bundle enter. The further increase 

 in the lobes can be seen from Figure 131. 



The meristematic tissue of the haustorium becomes more restricted as 

 the haustorium grows. Whereas in the very early stage (Figure 128) a 

 considérable portion of the haustorium is meristematic, in a stage repres- 

 ented by Figure 130 the cells of the outer two layers only are in active 

 division. In a stage represented by Figure 131, the inner of the two layers 

 has also ceased to divide. From that time on until the last of the endosperm 

 is absorbed the haustorium grows mainly through the elongation of the 

 cells of the periphery — that is the cells just within the Epidermis — and 

 also because of the increase in the size of the inter-cellular spaces. 



The distribution and arrangement of the spongey tissue is interesting 

 to note. In Figure 13Q, Plate XVII, several of the cells taken from the 

 interior of an haustorium are seen. The cells are more are less irregularly 

 stellate in character allowing for large spaces between the cells that corne 

 in contact with each other. The long axis of such a cell usually runs 

 parallel with the long axis of the haustorium. In the lobes the spongey 



