186 SUMMARY OF CURRENT RESEARCHES RELATING TO 



CRYPTOGAMS. 



Pteridophyta. 



(By A. Gepp, M.A., F.L.S.) 



Fertile Spike of the Ophioglossaceae.*— M. A. Chrysler discusses 

 the nature of the fertile spike in the Ophioglossaceae. He recapitulates 

 the theories that have been put forward by previous authors, describes his 

 own investigations, and gives the following summary. 1. The pair of 

 vascular bundles in the fertile spike of Botrychium virginianum arise 

 from near the edges of a trough-shaped and usually split leaf-trace. 

 Each of these bundles leaves a gap in the leaf -trace. Similar gaps occur 

 in other ferns. 2. Since the bundles running into the pinna? of the 

 sterile frond arise in exactly in the same way, it is inferred that the 

 fertile spike represents two fused basal pinnae. 3. In B. tematum and 

 B. obliquum there is a slight modification as to the gaps, which is 

 regarded as a reduction of the condition found in B. virginianum. 



4. In other species a further reduction is found, the gaps being absent. 



5. Abnormal specimens of B. obliquum show either a pair of fertile 

 spikes, or a pair of spikes with a single spike (fused pair) below. Such 

 cases are regarded as reversions. G. In Ophioglossum the bundles lead- 

 ing to the fertile spike break off from the two edges of the curved row 

 of strands which represents the leaf -trace. This condition is regarded as 

 derived from that of Botrychium. 7. In Helminthostachys the vascular 

 supply of the fertile spike is derived principally from one edge of the 

 curved row of bundles which forms the leaf -trace ; and it is inferred 

 that here the fertile spike represents a single pinna. 8. The Ophio- 

 glossaceae are related to the ferns, having sprung from near the level of 

 the Osmundaceae. They branched off from the primitive stock at a 

 very remote period. 9. A study of the internal structure of the leaf in 

 Ophioglossaceae affords strong support to Roeper's view that the fertile 

 spike represents two fused basal pinnae, though in certain cases a spike 

 represents a single pinna, which, however, does not rise ventrally. No 

 support is afforded to the view of a strobilar origin or of a direct 

 derivation from Hepaticae. 



Foliar Gaps in the Osmundaceae. f — E. W. Sinnott discusses the 

 presence of foliar gaps in the Osmundaceae. 1. He examined six species, 

 and found foliar gaps in all at the points where leaf-traces branch off 

 from the vascular cylinder, though sometimes obscured. 2. All fossil 

 Osmundaceae with parenchymatous pith show foliar gaps. 3. All young 

 Osmundaceae, with a single doubtful exception, show foliar gaps from 

 very early stages. 4. In seven species a gap in the arch-shaped leaf- 

 bundle was always found at the base of the trace to the pinna. In 

 three species this gap affected only the xylem, but in the remaining four 

 involved a complete break in the vascular tissue. 5. That foliar gaps 

 represent a primitive feature in the Osmundaceae is quite clear from the 

 fossil evidence and the structure of the young plant and the foliar 

 strands (both of which are ever conservative of ancestral characters). 



* Ann. Bot., xxiv. (1910) pp. 1-18 (2 pis. and figs.), 

 t Tom. cit., pp. 107-118 (2 pis.). 



