CHAPTER XI 



CLASSIFICATION OF THE HOMOSPOROUS LEPTOSPORANGIAT^ 



Fain. I. OsvmndacecE^ 



The Osmundaceae, which in many respects form a transition 

 from the eusporangiate to the leptosporangiate Filicineae, are 

 represented by two genera, Todea, with four species, mostly 

 confined to Australasia, one species only being found in South 

 Africa ; Osmunda, with six species, belonging mainly to the 

 temperate and warm temperate regions of the northern 

 hemisphere. The widely distributed species 0. regalis is 

 found also in South Africa, but otherwise they belong 

 exclusively to the northern hemisphere. Osmunda has the 

 large sporangia borne on very much modified sporophylls, 

 which recall strongly those of Botrychiuni or HelniintJwstachys ; 

 Todea, while its sporangia are like those of Osmunda, has 

 them borne upon the backs of ordinary leaves. 



The development of the gametophyte is completely known 

 in Osmunda^ and somewhat less perfectly in Todeaf which 

 does not, however, seem to differ essentially from Osmunda. 

 In the latter there is considerable difference in the species 

 examined. In all of them the spores contain chlorophyll 

 at maturity, and quickly lose their power of germination. 

 Sown as soon as ripe, they germinate very promptly, and 

 the first division of the spore often takes place within 

 twenty-four hours. The early stages show great variation, 

 even in the same species, and these seem to be often quite 

 independent of external conditions. The ungerminated spore 



^ Hooker and Baker (i). - Kny (5) ; Campbell (12). ^ Luerssen (3). 



