1034 SUMMARY OF CURRENT RESEARCHES RELATING TO 



apex of the mature root. In Angiopteris evecta tlie lateral roots also 

 originate in a group of four initial cells. 



The transition from the growing point of true ferns to that of the 

 Marattiaceae and flowering plants is accompanied by a lowering of the 

 centre of formation. Both in this respect and in the partial filling 

 up of the apical cell-cavity by radial walls, the Osmundaceae occupy 

 an intermediate position between typical Filices and Marattiaceae. 

 The co-axial structure, which first makes its appearance in the Os- 

 mundaceae, is strongly developed in the Marattiacese, and indicates 

 an approach to the structure of Gymnosperms. 



In the development of the sporangium Todea also exhibits a 

 transition to the Eusporangiatae. 



Structure and Classification of OpMoglossacese.* — Following up 

 his division of Ojphioglossum into the three subgenera Euophioglossum, 

 Ophioderma, and Cheiroglossa, Dr. K. Prantl uses, for further 

 diagnosis of the species belonging to the first subgenus, the venation 

 of the sterile branch, the length of the leaf-stalk, and the structure of 

 the exospore. 



The venation Dr. Prantl classes under two types, paraneural and 

 ptiloneural. In the first, the median vein does not branch, while the 

 lateral nerves which spring directly from the leaf-stalk dichotomize ; 

 the result being an arrangement similar to that of the leaves of 

 monocotyledons. In the second type the median vein, which reaches 

 the apex of the leaf, sends oif alternately secondary branches on each 

 side ; and the lateral nerves which spring from the leaf-stalk are very 

 subordinate. The leaf-stalk is either hypogsean or epigsean. The 

 exospore is always thickened in a reticulate manner, but exhibits 

 differences in the width of the meshes and the height of the ridges. 

 Of less importance from a systematic point of view are the form of 

 the epidermal cells of the stomata, the consistence of the leaf, the 

 number of leaves developed at the same time, the structure of the 

 stem and roots, and the presence or absence of adventitious shoots. 

 Under the subgenus Euophioglossum are arranged twenty-seven species; 

 Ophioderma and Cheiroglossa contain only one each, viz. 0. pendulum 

 and palmatum. 



The fifteen species of BotrycMum are arranged under the two sub- 

 genera Eubotrychium and Phyllotrichium already described. 



Morphology of Phylloglossum Druinmondii.| — Prof F. 0. Bower 

 reports some of the results of a successful cultivation of this little 

 known Cryptogam. From the smaller tubers, only vegetative organs 

 arise, in the form of a successive whorl of rounded leaves springing as 

 outgrowths from the broad apex. The apex of the axis, which is at 

 first central, becomes depressed and overarched, and forms the apex of 

 the new tuber. By peculiar localization of growth this is inverted, and 

 comes to project laterally from the parent plant, while on the oppo- 

 site side of the axis below the insertion of the oldest leaf the first root 



* Jahrb. K. Bot. Gart. Berlin, iii. (1884) (2 pis.). See Bot. Centralbl., xxii. 

 (1885) p. 135. Cf. this Journal, iv. (1881) p. 92. 

 t Pioc. Koy. Soc, xxxviii. (1885) pp. 445-7. 



