20 



The Tasmaniau species of Isoetes became very recently the 

 subject of Prof. Braun's masterly researches. From the 

 important memoir above quoted I have translated the cardinal 

 characters of the dia<j^noses, which I here the more readily 

 subjoin, as the essay will not be easily accessible to Australian 

 observers. The repetition of some of the characteristic notes 

 was deemed necessary to contrast the four Tasmanian species 

 with three or four from continental Australia, and with several 

 other, to us, exotic species, those of Tasmania being all 

 endemic. It is, however, possible that some of them may yet 

 be discovered in the Australian Alps, or in the rivers of the 

 lowlands of Victoria. 



Isoetes Gicnii, Al. Br. L. C, and Monats Berrichton, 22 July, 

 1869. Lacustrial ; rhizome three-lobed ; leaves short, very 

 stout, rigid; cuticle olive- brown, thick; sheath brown; stomata 

 absent ; vellum, none or rudimentary ; sporangium small, 

 upwards flat, acute at the margin, with copious sclerenchymatic 

 cellules, macrospores very large, beset with numerous minute 

 tubercules, microspores indistinctly tuberculate. In alpine 

 lakes. 



*Isoetes elatior, F. M. in Linnea 1852, 722 ; Al. Br. L. P. 

 536. 



Fluvial ; rhizome 3-lobed ; leaves very long, flaccid, green ; 

 sheath pale ; stomata absent ; velum none or rudimentary ; 

 sporangium pitch-coloured, upwards flat, at the margins acute 

 with copious sclerenchymatic cellules; macrospores moderately 

 large, pale, beset with numerous minute tubercules ; micros- 

 pores distinctly tuberculate. South Esk. 



* Isoetes Immiliar, F. M., L. P, 722 ; I. Hookeri, Al. Br. 

 L. P. 538. 



Fluvial, rhizome, bilobed ; leaves hard ; cuticle thick, turn- 

 ing brown ; sheat brown, short ; stomata absent ; vellum 

 complete ; closed, brown ; sporangium without sclerenchymatic 

 cellules ; macrospores rather large, pale, beset with numerous 

 minute tubercules ; microspores intensely brown, short tuber- 

 culate, South Esk. 



Isoetes Stuartii. Al Braun, L. P., 539. 



Fluvial ; rhizome two-lobed ; leaves rather slender and soft, 

 green ; cuticle thin ; sheath pale ; stomata absent ; vellum com- 

 plete, closed, pale ; sporangium mottled with brown and pale 

 thickened sclerenchmatic cellules ; macrospores rather large, 

 pale, beset with numerous minute tubercules. South Esk. 



An excellent series of specimens of Isoetes, very obligingly 

 secured by the Honourable W. Archer, from the waters of the 

 Western Mountains, are since some time in the hands of 

 Monsieur Durien de Maisonneuve, for elucidation in his illus- 

 trated monography of the genus. 



