50 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Azolla growing in the British Isles [% A. filiculoides, and thai the records 

 of A. caroliniana arc based upon error. Ee adds some notes on the 

 receni spread of the plant over the Norfolk Broads. 



Dryopteris.*— C. Christensen publishes notes on some species of 

 Dryopteris recently collected in tropical America, two of which — 

 D. (Lastrea) Shaferi and D. (Lastrea) Jimemzii — are new to science ; and 

 their characteristic structure is described. In discussing the peculiarities 

 of D. {Stigmatopteris) cyelocolpa the author claims that Stigmatopteris is 

 worthy of generic rank. 



Ferns of Lord Howe Island.! — W. W. Watts publishes some 



additional notes on the ferns of Lord Howe Island — the result partly of 

 a recent visit to the island by R. B. Oliver. He founds a new species, 

 P. Whiteleggei upon the plant locally known as " heavy fern,' 1 and states 

 that his previous species P. Kingii is to be referred to P. Moorei Christ. 

 Three species of Dryopteris grow in the island, and have been the subject 

 of some confusion. Marattia fraxinea var. salicina appears to be a valid 

 variety. Ophioglossun vulgatmn var. lanceolatum is a variable plant 

 and has been split into various species by previous writers. Four tree- 

 ferns occur in the island ; and Oliver's careful field-notes concerning 

 their trunks, stipites, rhachises, costas, etc. are incorporated ; and a new 

 description of Alsophila robusta C. Moore is added. 



Bryophyta. 

 (By A. Gepp.) 



Morphology and Development of Symphyogyna.^: — Florence A. 

 McCormick publishes a study of Symphyogyna aspera,a Mexican hepatic, 

 and gives the following summary : 1. The thallus has a central strand 

 of greatly elongated cells which taper at both ends. The walls of these 

 cells have narrow pores, spirally arranged. 2. The species is dioicous ; 

 and the male plants are more slender than the female. 3. The anther- 

 idia are dorsally scattered over the thickened part of the thallus, each 

 antheridium being surrounded by a scale. 4. The archegonia occur in 

 groups on the dorsal side of the thallus, each group being on a pad-like 

 extension of the thallus and surrounded by an involucre. 5. More than 

 one embryo may be formed in a group, but so far only one has been 

 found to reach maturity. 6. As the embryo elongates, the calyptra and 

 pad also elongate ; and the old archegonia are left on the tip of the calyptra. 

 7. The young embryo develops by segmentation similar to that formed 

 by a dolabrate apical cell. 8. The sporogenous tissue is differentiated 

 relatively late in the history of the sporophyte. <). The cells which are 

 to form elaters may early be distinguished from the cells which arc 

 ultimately to give rise to the spore-mother-cells. The former cells 



* American Fern Journ., iv. (1914) pp. 77-83. 



t Proc. Linn. Soc. N.S.W., xxxix. (1914) pp. 257-62. 



1 Bob. Gaz., lviii. (1914) pp. 401-18 (3 pis.). 



