340 



BOTANICAL GAZETTE 



[ilAY 



AN ABNORMAL PORELLA PLATYPHYLLA 



(with three figures) 



In examining some material of Porella platyphylla I found one arche- 



gonium which differed 



structure 



If the 



This internal difference consisted in the presence 

 of two perfectly formed egg cells, each with a 

 row of canal cells {-jig. i). There were also 

 two ventral canal cells. One row of the canal 

 cells, as will be seen from fig. i, was somewhat 

 shorter than the other; the number of cells in 

 each, however, was the same. The egg cells 

 with the canal cells taken together occupied a 

 somewhat larger space than is usual in this 

 plant. The archegonium shown here was 

 larger than those usually found. The two egg 

 cells and canal cells were only clearly seen when 

 lying in the plane shown in figu 

 archegonium was viewed at right angles to this 

 position, they were difficult to see. This speci- 

 men was gradually brought into a strong solu- 

 tion of glycerin and allowed to become clear; 

 it was then drawn with a camera lucida. 

 Porella platyphylla also often shows branched elaters.^ Fig, 2 ^hows 

 one slightly branched at the end; fig, 3 shows a more pronounced instance 

 of such branching. In some elaters branching of the larger branches 

 was noticed, which formed a rather complicated figure. The spiral 

 thickenings were often very difficult to follow with certainty at the point 

 of branching. Fig. 2 shows their arrangement in one specimen.— i' . -^^a- 

 Andrews, Leipzig. 



4 See also: Coker, W. C, On the occurrence of two egg cells in the archego- 

 nium of Mnium. Bot. Gazette 35:136. 1903. 



Bliss, Mary C, On the occurrence of two venters in the archegonium of Poly- 

 trichum. Bot. Gazette 36:141. 1903. 



Lyon, Harold L., Polembrj^ony in Sphagnum. _ . 



Goebel, K., Homologien in der Entwicklung miinnlicher und weiblicher Ge- 

 schlechtsorgane. Flora 90:277. 1902. 



Box. Gazette 39:365- ^9^5- 



sSee also: Campbell, D. H., Mosses and ferns. 2d ed. 1905. 



