356 The Ohio Naturalist. [Vol. V, No. 8, 



quite reasonable to expect to find them where the archesporium 

 is so commonly multicellular. But in Batrachium, or at least in 

 the material collected for study, the number of megaspores which 

 divide and the number of embryo sacs that develop embrvos 

 seem very few. In many cases only a few of the ovules matured, 

 perhaps two or three, as was seen in the ripened carpels and also 

 in the material sectioned. 



The functional megaspore passes through the two, four and 

 eight celled stages and the nuclei arrange themselves normally 

 (Fig. 20-23). The two synergidae stain much darker than the 

 egg cell and the antipodals than the polar nuclei. After the 

 conjugation of the polar nuclei the resulting definitive nucleus 

 was very readity distinguished by its enormous size (Fig. 24). 

 While the polar nuclei are approaching each other the antipodals 

 enlarge and seem to take on definite walls, and the embryo sac 

 begins to widen below. At the time of fertilization the anti- 

 podals are situated in an elevated crater-like pouch (Fig. 24). 

 The lengthening of the embryo sac is greater on the distal than 

 on the proximal side and extends beyond the chalaza near where 

 the antipodal pouch is situated. The antipodals are typically 

 those of Ranunculaceae resembling almost exactly those of R. 

 delphinifolius. The nuclei sometimes divide (Fig. 27) but usually 

 only three were present. They persist for a long time staining 

 quite deeply and can be distinguished even in quite mature 

 ovules (Figs. 31 and 33). 



The entrance of the pollen tube into the embryo sac and the 

 actual phenomenon of fertilization was not observed in Batra- 

 chium. The pollen tube was traced well down into the stigmatic 

 tissue, found emerging in the cavity of the ovulary and again 

 seen among the glandular cells of the shorter integument and 

 traced into the micropyle. One might expect anything since 

 Overton (10) reported parthenogenesis in Thalictrum pur- 

 purascens, Coulter (3) found the second sperm cell much disor- 

 ganized at the time of its discharge in Ranunculus septentri- 

 onalis and Miss Thomas (14) discovered double fertilization 

 occurring in Caltha palustris. Double fertilization is also 

 reported by Nawaschin (11) for Delphinium elatum and by 

 Guignard (7) in Ranunculus flammula, R. C3^mbalaria, Anemone 

 nemorosa, Helleborus foetidus, Nigella sativa and N. damascena. 

 In Batrachitmi, the fact that so few ovules develop and the 

 traces of the pollen tube found in those that do, seems to set aside 

 entirely the occurrence of parthenogenesis. The peculiar pale 

 nucleus shown in Fig. 2G may be the second sperm nucleus. In 

 one slide there was what might be taken for double fertilization, 

 but the evidence was so unsatisfactory that the writer prefers to 

 leave the question unsettled. 



