INVERTEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 597 



embryo from which the stem is formed ; the posterior half of the em- 

 bryo (the " hypobasal " half, from which in Marsilea and Polyi)odiacefB 

 the root is formed) appears in Salvinia only as a swelling or " bulb" 

 at the base of the pedicel. 



4. The " pedicel " of Salvinia corresponds therefore, in its origin 

 and develo2:)meut, to the pedicel of the sporogonium in Hepaticaa. 



5. The embryo of Salvinia bears a closer resemblance than that of 

 any other vascular cryptogams to the embryo of Hejiaticfe, since in 

 the latter the " bulb " and " pedicel " are similar in origin and 

 development ; the ultimate diflfcrence depends on the " apical octants," 

 which in the Hepatica3 enter partially or entirely into the formation 

 of the sporogonium, while in Salvinia they take part in the formation 

 of the " peltate leaf" and the stem. 



Adventitious Buds in Ferns. * — Accepting Mettenius's definition 

 of adventitious buds as " those which arise, equally independently of the 

 base of the leaf with those which result from dichotomy, in the form 

 of a new formation beneath the growing-point of the main axis," the 

 lateral buds described imder this category by Hofmeister in Pteris 

 axjuilina, Aspidium filix-mas, Asplenimn filix-femina, Stndliiopteris 

 germanica, and Asj^lenium Belangeri, must, with the exception of those 

 of the last-named species, be excluded from it. To the list of ferns 

 producing true adventitious buds on the lamina of the frond 

 Heinricher now adds Diplazium celtidifolium, Aspleniuni hulhifernm, 

 and A. viviparum. The following is an epitome of the results of 

 his observations : — 



1. The adventitious buds of ferns are united to the parent organ 

 by the course of the vascular bundles. 



2. The position of the buds varies ; but is constant in the same 

 species within certain limits. 



3. In all the cases examined, in their later stages, at all events as 

 soon as a frond is formed, the buds grow by an apical cell which 

 becomes segmented triangularly. 



4. In earlier moderately advanced stages, but before the formation 

 of a frond, an apical cell is scarcely ever to be recognized. 



5. But in the youngest stages observed, an apical cell with 

 triangular segmentation could be detected. 



6. The origin of all the buds is exogenous, and the series of their 

 stages of development points to an acropetal succession. 



7. The buds may proceed from a single superficial cell, in which 

 a triangular apical cell is formed. 



8. The origin of the buds is at a very early period. The separa- 

 tion of the parent-cells of the adventitious buds can apparently not 

 take place too far from the apex of the frond or of the pinna. 



Production of the first vegetative Shoot of Equisetum palustre.t 

 — From the prothallium of Equisetum arvense, palustre, variegatum 

 and probably other species, is produced first of all a vegetative shoot, 

 which soon perishes, distinguished from the permanent ones by the 



* ' SB. Akad. Wiss. Wien,' Isxviii. (1878) p. 249. 

 t ' Bot. Zeit.,' xxxvii. (1879) p. 289. 



