198 Pteridophyten. 



Bruyn, H. de, The ontogenetic development of the Stele 

 in two species of Dipteris. (Ann. Bot. XXV. p. 762—772. pl. 

 57—58. 1911.) 



The earliest ontogenetic phase of the stele of Dipteris is the 

 protostele (found only in D. Lobbiana owing to the earliest stages 

 of D. conjugata, in which it probably obtains, not being available); 

 parenchyma appears in the centre of the protostele and later the 

 latter becomes amphiphloic; in D. conjugata the xylem of the am- 

 phiphloic protostele is frequently much thicker on the ventral than 

 on the dorsal side and this may be true of the early stages of the 

 solenostele in this species. Indications of the thickening of the leaf 

 gap were found in quite young solenostelic plants of D. conjugata, 

 but did not occur in D. Lobbiana. In D. conjugata the petiole con- 

 tains a Single arched vascular bündle which onty forks at the upper 

 end of the petiole; this is true too of the earlier leaves of D. Lob- 

 biana, but in the later leaves the foliar bündle may be double in 

 the lower part of the petiole; the two bundles fuse again to branch 

 once more before entering the lamina. In this species the latest 

 formed traces available were separated successively as two cylin- 

 drical Strands. Isabel Browne (University College London). 





Campbell, D .H., The Eusporangiatae ; the comparativemor- 

 phology of the Ophioglossaceae and Marattiaceae. (Carnegie 

 Inst. Washington, Publ. CXL. p. 6—229. pls. 13. figs. 192. 1911.) 



In this publication Campbell has summarized his studies of the 

 Ophioglossaceae and Marattiaceae, extending through twenty years 

 and with unusual opportunities for collecting tropical material. These 

 groups are of very great interest, since they seem to represent the 

 plexus from which Gymnosperms have arisen, and also, according 

 to Campbell, because they have probably been derived directly from 

 Bryophytes. In addition to the argument for the primitive character 

 of Ophioglossum, the real genetic relationship of Ophioglossaceae 

 and Marattiaceae is established more firmly than ever before, so 

 that the inclusion of both groups in Filicales seems to be a necessity. 



It is assumed that the sporophyte of Ferns has been derived 

 from the sporogonium of Bryophytes, and also that the sporophyte 

 in general has arisen as an antithetic generation. The ferns are so 

 ancient that it is hopeless to expect to find their predecessors, but 

 probably the small and delicate species of Ophioglossum most 

 resemble them, and the sporogonium of Anthoceros probably most 

 resembles the ancestral Bryophyte. As contrasted with the Lepto- 

 sporangiates, the closer connection of the Eusporangiates with the 

 Bryophytes is emphasized by the late development of the organs 

 of the embryo and the very much larger embryo before entire 

 independence from the gametophyte is attained. Attention is called 

 to the fact that several roots and leaves may have developed, or 

 even spores may have appeared, before the independence of the 

 sporophyte is complete. The young sporophytes of Ophioglossum 

 and Anthoceros are shown to resemble one another very closely, 

 the bulbous foot being in common, and the meristematic zone and 

 capsule of Anthoceros being represented by the growing point of 

 the root (which penetrates the foot and enters the soil) and the 

 cotyledon of Ophioglossum. This cotyledon in existing species is 

 sterile, but the "pro-Ophioglossum" or "pro-fern" is pictured as 



