830 RECORD OF CURRENT RESEARCHES RELATING TO 



period beneath a cover-glass flooded with water. A part of the 

 prothallium having decayed, there sj^rung from all parts of the sound 

 portion a number of peculiar conferva- or protonema-like adventitious 

 shoots. The production of similar adventitious shoots was easily 

 excited in other healthy prothallia by placing them in similar con- 

 ditions. After the lapse of time these adventitious shoots exhibited 

 a tendency towards lateral branching, thus becoming secondary 

 adventitious prothallia. This is regarded by the author as ex- 

 hibiting an interesting phylogenetic affinity with the conferva-like 

 protonema of mosses. The prothallium of a fern must be looked on 

 as an amphibious structure intermediate in its vegetative and repro- 

 ductive properties between aquatic and terrestrial structures. 



Synopsis of the Species of Isoetes.* — Mr. J. G. Baker distin- 

 guishes 46 species, of which he gives brief diagnoses, dividing them 

 into 4 groups as follows : — 



I. Aquatics. 

 Velum nullum. 1. I. triquetra A. Br. 2. I. Gunnii A. Br. 3. I. 



elatior F. M. 

 Velum partiale. 4. I. lacustris L. 5. I. echinospora Dur. 6. /. 



azorica Dur. 7. I. jjygmce.a Engelm. 

 Velum completum. 8. I. Stuartii A. Br, 9. I. Lechleri Metten. 



II. SUBAQtJATIC^. 



A. North American species, with a 2-lobed rootstock. 



Velum partiale. 10. I. Bolander I 'Engelm. 11. I. TucJcermani A.Br. 



12. I. saccharata Engelm, 13. I. riparia Engelm. 

 Velum completum. 14. I. nielanospora Eugelm. 



B. Australian and New Zealand Species, with a 3-lobed rootstock. 

 15. I. Mijlleri A. Br. 16. I. Kirhii A. Br. 17. I. alpina Kirk. 

 18. I. Drummondii A. Br. 



III. AMPHIBIiE. 



A. Eootstock 2-lobed (all North American species). 



Velum partiale. 19. J. Butleri Engelm. 20. I. melanopoda J. Gay. 



21. I. Engelmanni A. Br. 

 Velum completum. 22, I. NuttalUi A. Bx*. 23.2. fiaccida Shuttle w. 



B. Eootstock 3-lobed. 



1. Species of the Mediterranean region : — 



Velum nullum s. parum evolutum. 24. I. setacea Bosc. 25. /. 



adspersa A. Br. 26. 1. malinverniana Cs. et de Not. 

 Velum fere s. totum completum. 27. I. velata A. Br. 28. I. Peral- 



deriana Dur. et Letouru. 29. I. dubia Gennari. 30. I. tegulensis 



Gennari. 31. I. Boryana Dur. 32. I. tenuissima Boreau. 33. 



I. olympica A. Br. 



2. Species of Tropical Africa : — 



34. I. Wchcitschii A. Br. 35. I. nigritiana A. Br. 36. I. Schwein- 

 furthii A. Br. 37. I. cequinoctialis Welw. 



* ' Trim. Joiu-n. Bot.,' ix. (1880) pp. G") and 105. 



