The Genus Riccardia in Chile. 107 



the branch thus becoming greatly elongated. In most cases the 

 branch which bears a male inflorescence is simple, but in a few 

 species the male branch divides almost immediately into two or 

 more subequal branches, each of which bears an inflorescence. 

 This is strikingly the case in R. Thaxteri (Fig. 2, B) and R. flori- 

 biinda (Fig. 12, A, B), where the inflorescences tend to form 

 divaricate clusters. 



The female branches, as a rule, are shorter than the male 

 branches. In a few species, however, particularly in the absence of 

 fertilization, more elongated female branches are developed, and 

 an extreme case is found in Aneura liymenophytoides Spruce 

 of Ecuador, where as many as twenty archegonia are sometimes 

 present (see 23, p. 542). Although the archegonia are borne on 

 the dorsal surface of the branch, the latter is sometimes twisted in 

 such a way that the archegonia are turned forward (toward the 

 apex of the higher axis) rather than upward. The protective 

 structures of the inflorescence are usually more complicated than 

 in the case of the male inflorescence, although this is not always the 

 case. The wing of the branch, for example, tends to be broader 

 and to be dentate or laciniate (see Figs. 2, I, y, I, and 12, H), and 

 a similar but narrower lamella is sometimes present between a wing 

 and the archegonia (see Fig. 9, F) ; in other cases scattered teeth 

 or cilia may be present among the archegonia. In case fertiliza- 

 tion takes place a massive tubular protective organ develops around 

 the young sporophyte (see Figs. 2, A, and 10, A). This organ is 

 usually described as a calyptra and this usage will be followed in 

 the present paper. It has long been known, however, that only a 

 small portion of this calyptra is derived from the ventral wall of 

 the fertilized archegonium (see Leitgeb, 15, p. 47). Most of it rep- 

 resents new tissue developed by a meristematic zone below the 

 archegonium. The calyptra is therefore a lateral marsupium or 

 perigynium, as Goebel has so clearly shown (12, p. 722, /. 70^). 

 Another remarkable feature is due to the fact that the neck-cells 

 of the fertilized archegonia are likewise stimulated to renewed 

 growth, although it is doubtful if they undergo division. The 

 neck-cells increase markedly in size and their walls become thick- 

 ened. They thus form at the tip of the calyptra a conical or 

 rounded appendage known as a corona. In some species this 

 corona is small and inconspicuous, while in others it is large and 



