018 SUMMARY OF CURRENT RESEARCHES RELATING TO 



ill pairs, and arc sbortly-stalkcd spherical bodies presenting nothing 

 very strikim^ in their structure. Tho archegouia arc borne on arche- 

 qoniovliori's or massive outgrowths of tho prothallus, each archegoniophoro 

 bcariuf citlicr a single archegonium or a number. The archegoniophoro 

 is usually a multicellular structure, and tho venters of the archegonia 

 are imbedded in its tissue. Tho species is probably dioecious. In old 

 fronds there is an additional niodo of propagation by direct budding, 

 resulting in the formation of new sporophytes. 



In T. alaium Prof. Bower supplements his previous description of 

 aposporous and apogamous developments.* Although normal sporangia 

 and spores are in some cases produced, tho greater number of the 

 prothalli observed were formed, not by germination of spores, but by 

 peculiar aposjiorous growths which arise in remarkable profusion from 

 such old fronds as have fallen to tho ground, or even from the tips of 

 piunfe of fronds which still retain their normal position. The prothalli 

 differ from those of T. pyxidifermn in being frequently not protonemal, 

 but flattened structures. Tliey may arise from the surface of tho frond 

 or from the sporangium, with or without the intervention of protonemal 

 filaments. On their apices are very frequently produced in great 

 numbers the remarkable spindle-shaped gcmmfo borne on sterigmata. 

 The protonemal filaments and the prothalloid growths may pass 

 insensibly one into ai^.other. From tho filaments are produced either 

 rliizoids or protonemal branches. Tho mature gemmro are composed of 

 from five to seven cells ; they germinate only with extreme slowness. 

 The antheridia are produced on the protonema, but have never been 

 seen to produce antherozoids ; and no archegonia have ever been seen 

 on cultui-es of this species. The author believes that this species is 

 never reproduced sexually; apogamous budding is common on the 

 protonema. 



As regards the bearing of these facts on the phylogenesis of Ferns, 

 Prof. Bower thinks there can be no doubt that the HymenophyllacesB 

 must be regcirded as the lowest family of Ferns, and that the protonema 

 of Tricltomanes corresponds to the protonema of a Moss. The oophyte is 

 probably the more ancient of the two generations in the Filicinea3, but 

 is adapted only to conditions of great and tmiform moisture. For the 

 dissemination of the spores of tho sporophyte dryness is in most cases 

 essential ; and when the fern grows in very moist situations, as is the 

 case with the Hymcnophyllacefe, we have the dissemination of the 

 spores in abeyance, and a general reversion to aposporous reproduction. 



Development of Onoclea Struthiopteris Hofim. (Struthiopteris 

 germanica Willd.)."!" — Dr. D. H. Campbell publishes a very careful and 

 detailed account of the develoj)meut of the " ostrich fern." The spores 

 have, when mature, three distinct coats, a brown exospore, furnished with 

 ridges and folds, and two inner coats. The prothallium is distinctly dioe- 

 cious, the female prothallia being usually larger than the male. By con- 

 tracting and staining, the continuity of protoplasm from cell to cell of 

 the prothallium can be clearly demonstrated. The antheridia and arche- 

 gonia are distinctly trichomic in their origin, the latter are much more 

 limited in their distribution than the former. The ventral canal-cell of 

 Janczewski docs not appear to exist in the archegonium. The actual 



* 8ee this Journal, ante, p. 202. 



t Mem. Bobt. Soc. Nat. Hist., iv. (1887) jip. 17-52 (4 pis.). 



