160 Bulletin Jard. Bot. Buitenzorg, Série III, Vol. V. Livr. 2. 



fissile takes on a definite arrangement, the vascular bundie serving as a 

 center around which the tissue orients itself. Such a lobe is seen in 

 Figure 140, Plate XVII. Roughly analyzed the bundie is the center, 

 then follows a ring of cells completely encircling the bundie. From 

 this ring rows of cells like the spokes from a hub radiate. Thèse rows may 

 be one, two or three cells in length. Encircling thèse radiating cells like 

 the rim of a wheel are additional cells. Then follow one or more layers 

 of encircling cells or radiating cells in part and finally the epidermal layer. 

 The innermost cells show the greatest degree of expansion, the outermo'st 

 cells are still capable of expanding so that subséquent growth of the lobe 

 mey be merely the resuit of increase in the size of the inter-cellular spaces. 

 The fully grown haustorium is a very light object. Its spongey character 

 can be readily seen with the unaided eye when it is eut through with a 

 knife and the zones too are discernable. Figure 110, Plate XII, brings out 

 the spongey zone represented by the dotted area and the outer zone corh- 

 posed of the epidermis, the meristematic layers and vascular bundles. 



Ferment and meristem cells. 



Thèse cells were clearly described by Sachs (^') and it is surprising 

 how closely the cells of the haustorium of Elaeis resemble those described 

 by Sachs for Phoenix. In their arrangement the layers differentiate them- 

 selves from each other. Thus the cells of the outermost layer show a 

 distinctly epidermal character. In the resting embryo as we hâve already stated, 

 no sharp line can be drawn between thèse cells of the haustorium and the 

 cells of the cotyledonary sheath. The meristematic cells of the next layer 

 are in the main cubical and those of the third layer run with their long 

 axes parallel to the long axis of the haustorium. Figure 112, Plate XIII is 

 from a section of a stage of the haustorium shown in Figure 128, Plate 

 XVI. The row of cells to the right shows the columnar epidermal cells, the 

 so-called ferment cells, whose function undoubtedly is associated with 

 enzyme sécrétion. As can be seen from the plate their tendency is 

 to be rectangular and it truly merits the name columnar epidermis or 

 epithelium. The free ends of the cells of the epidermis are rounded 

 whereas the other end may be angular when the cells corne in contact 

 with irregularities in the cells of the inner layer or they may also 

 become wedge-shaped as the third cell from the bottom of the layer 

 shows. The nucleus is always centrally located, agreeing with Reed's (") 

 observations in Phoenix dactylifcra. The cytoplasm is dense and very 

 granular with many large and small vacuoles scattered within it. The 

 vacuoles show no sélective arrangement in the cell. In one cell the 

 larger vacuoles appear at the distal end, in another cell at the proximal 

 end, in still others at both ends and lastly they may cluster around the 

 nucleus. 



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