200 



.MORPHOLOGY OP ANGIOSPERMS 



gest as wide a range of variation as among Monocotyledons, 

 though not so clearly related to great groups. 



In Geranium, as has long been known, while the Capsella 

 type is maintained in general, there is no hypophysis, the root- 

 tip being covered by the tissue of a massive suspensor. 



In Pcperomia pellucida Campbell''" and Johnson 1 '- have 

 both observed that the first segmentation of the fertilized egg 

 is vertical, followed by a transverse division, and that there is 

 no indication of a suspensor. 



In Loranthus sphaerocarpus Trenb 22 has described the first 

 division of the fertilized egg as vertical, as in Peperomia, but 

 followed by transverse divisions, so that the proembryo resem- 

 bles two filaments lying side by side (Fig. 91). The two basal 

 cells elongate enormously, forming a suspensor as in Gymno- 

 sperms, whose length is increased by the moderate elongation 

 of the second pair of cells, and which becomes more or less tor- 

 tious, the cells twisting about one another. In L. pentandrus 

 (Treub 2l! ) the elongating suspensor early forces the embryo 

 against the resistant base of the sac, where it become- much 

 flattened out, and for a time bears little resemblance to an em- 



Fig. 92. 



(still 



out 



B 



-Loranthus pentandrus. A, young embryo advancing into endosperm; thiok- 

 led tissue at base of sue deeply shaded; ,, embryo; s, suspensor; \ SS ; £. later 

 e, the embryo has reached the resistant base of the sae and has become flattened 

 ; x Hi— After Treub.m 



bryo ( Fig. 92). In Myoporum, as described by Billings, 70 the 

 suspensor is also extremely long and filamentous, forcing the 

 voting embryo down into the principal mass of endosperm, 



