QUEKETT MICROSCOPICAL CLUB. 347 



develops, it assumes quite a different form from that of tlie 

 seedling stage, but some members of this group only depart 

 from the embryonic form to a slight extent dm*ing the whole 

 of their life. Therefore we may fairly consider this group to 

 represent the primitive stages from which the more complicated 

 members of the genus have step by step developed." Instances 

 were given here, and sketches illustrating the various stages 

 were drawn upon the blackboard, making the matter very clear 

 and definite to those present. Mr. Brown remarked that, before 

 proceeding to trace a connection from species to species, it is 

 necessary to understand the structure of the plants. In this 

 connection he said : " If a transverse section of the body is 

 made, it is found to consist of an elliptically shaped slice of 

 soft, watery tissue, with a small, narrow, slit-like cavity at its 

 centre, corresponding to the orifice at the top." A flattened 

 tubular canal extends from the orifice almost to the base 

 of the plant, where, at the right season, either a young flower- 

 bud or a young vegetative bud will be found. If a flower, 

 it will ultimately grow up, push through the orifice, and expand. 

 At the base of the flower-stalk, inside the plant, one or two 

 vegetative buds form. At the very base of each plant the tissue 

 becomes firmer, sometimes more or less woody, finally assuming 

 the character of an extremely short, or more or less elongated 

 stem, according to the species. The solid-looking body of the 

 plant is really formed of two opposite fleshy leaves, united to 

 each other, with the exception of the canal which runs down the 

 centre. All the specimens in the pot passed round were con- 

 structed in this way, so that each is stemless, or nearly so, and 

 consists of a pair of simple fleshy leaves united into a single 

 obconic or globose body, thus representing a very primitive type 

 of plant so far as the vegetative organs are concerned, whilst the 

 flowers are of a highly complicated structure. The manner of 

 growth is remarkable. During the summer the vegetative buds 

 in the interior, at the bottom of the canal, gradually develop, and 

 as they enlarge the water and food material stored up in the fleshy 

 leaves is gradually absorbed, so that the visible part appears as 

 if the plant is dying, and at length becomes a mere dry, crumpled 

 skin, concealing the young growth, which ultimately bursts 

 through. 



" In tracing the gradual evolution of the more complex forms 



