578 SUMMARY OF CURRENT RESEARCHES RELATING TO 



(Ecological Sketch of the Flora of Santo Domingo.* — J. W. 

 Harshberger gives a short account of the topography, climate, and 

 vegetation of this island which he describes as the geographic centre of 

 the Greater Antilles. The vegetation is rich and most luxuriant, and the 

 writer describes its characteristic features under cecological headings : — 

 Hydrophytes, mesopbytes, forest vegetation, savanna vegetation, epi- 

 phytes, parasites, and xerophytes. On the slopes of the higher mountains 

 inland the native flora has been undisturbed. 



CRYPTOGAMS. 



Pteridophyta. 



"Analytical Key for the Ferns of the North-eastern States, based 

 on the Stipes.t — C. E. Waters has revised and enlarged his previously 

 published key, which is designed as an aid to identifying ferns when they 

 cannot be obtained in fruit. It includes 59 species which are arranged 

 primarily according to the number of the bundles in the leaf-stalk, and 

 secondarily according to the shape, regular or irregular arrangement, and 

 relative size of the bundles. A description of the leaf is also given under 

 each species. 



Filmy Ferns of South America.!— E. G. Britton discusses the so- 

 called Trichomanes radicans of the southern United States, and is of 

 opinion that the plant is quite distinct from that species and should be 

 called T. Boschianum Sturm. She claims that the Linnsean type of 

 T. radicans requires re-examination, and that its synonymy ought to be 

 revised ; that the type of T. scandens ought also to be re-studied ; and 

 finally that diligent search should be made in Florida for T. Petersii, 

 the specimens of which are lost and its locality doubtful. 



New Species of Selaginella. § — G. Hieronymus makes a second 

 contribution to his descriptions of new or insufficiently known species 

 of Selaginella, the names of most of which he has already published in 

 Engler and Prantl's Pflanzenfamilien. In the present paper he confines 

 himself to the subgenus Heteropliyllum, describing 20 species and adding 

 critical remarks. 



Bryophyta. 



Forcible Discharge of Antherozoids in Asterella californica.|| — 

 G. J. Pierce describes the forcible ejection of the antherozoids in this 

 liverwort, better known as Fimbriaria californica. The antherozoids 

 are discharged while enclosed in mucilage, the main mass of which 

 breaks up during its flight into smaller masses, so that finally the male 

 cells fall to the ground in little groups, the enveloping mucilage then 

 dissolves in the dew or rain, thus liberating the antherozoids which are 

 then free to swim off. The mechanism of ejection consists of two parts : 

 (1) the water-absorbing matrix consisting of gelatinised mother-cells 

 and thin walls, in which the antherozoids lie, and which distends the 



* Proc. Acad. Nat, Sci. Philadelph., liii. (1902) pp. 554-61. 



t Johns Hopkins Univ. Circular, xxi. (1902) pp. 83-5. 



% Bull. Torr. Bot. Club, xxix. (1902) pp. 475-7. 



§ Hedwigia, xli. (1902) pp. 170-202. 



|| Bull. Torr. Bot. Club, xxix. (1902) pp. 374-82 (6 figs, in text). 



