142 Report of the Microscopical Section. [Sess. 



structure. From the ventral side spring numerous unicellular 

 rhizoids of two kinds — one with smooth walls, and the other 

 with thickenings projecting into the internal cavity. It is not 

 too much to say that in these thickenings we have a primitive 

 vascular system. On the dorsal surface are numerous small 

 cup-shaped outgrowths containing from four to eight flat 

 stalked bodies called gemmae. These gemmae form the means 

 of a vegetative reproduction of the plant. The sexual repro- 

 duction is formed by means of antheridia and archegonia pro- 

 duced on different individuals, the plant being dioecious. 

 These sexual organs are borne on special erect branches which 

 spring from the thallus — the male branch terminating in a 

 lobed disc, and the female in a disc of nine rays. As in the 

 pteridophyta, fertilisation takes place under water. In this 

 family there is also a well-marked alternation of generation, 

 the sexual being the more highly developed. 



The Mosses. — These form a very numerous family, it being 

 stated that there are upwards of fourteen thousand species 

 spread over the face of the earth. The species studied was 

 Funaria hygrometrica, a small plant growing on the ground or 

 on old walls. Like almost all the other mosses, it has two 

 modes of reproduction — an asexual and a sexual. The asexual 

 arises from buds or gemmae produced on the rhizoids, and the 

 sexual by means of antheridia and archegonia. Funaria is 

 dioecious, — that is, the male and female organs are borne on 

 different plants. This, however, is not the case in all mosses, 

 many genera of which are monoecious. The antheridia arise 

 at the growing point of the male plant ; they are club-shaped, 

 and at maturity open on access of water, when the spermatozoid 

 mother-cells are expelled. The mucilaginous cell-walls of 

 these mother-cells disappear and the spermatozoids are thus 

 set free. When the plants are covered with moisture the 

 spermatozoids find their way to the archegonia of the female 

 plants, and fertilisation is effected by the spermatozoids pene- 

 trating the neck-canals of the archegonium, and thus reaching 

 the ovum, with which one of them unites. 



The fertilised ovum begins at once to grow, and finally 

 ruptures the archegonium, the upper portion of which is borne 

 aloft on the top of the growing ovum, to which it forms a 

 conical covering called the calyptra. When this fertilised 



