THE HIGHER CR1PT0GAMIA. 73 



antheridia in the axils of the leaves of the shoot which has 

 archegonia at its apex. This is the case with Lophocolea 

 lieterophylla and Radula complanata, and frequently, but 

 not always, with Jungermannia divaricata, all of which are 

 nearly allied to Zojj/iocolea bidentata. Frullania dilatata, 

 a very free-fruiting species, certainly does not very often 

 produce antheridia, Here, however, the mode of growth 

 of the plant, is such as greatly to facilitate the passage of 

 the contents of the antheridia to the archegonia. The 

 patches of Frullania, which are in a dry situation, and at 

 some height from the bottom of the tree on which they 

 grow, are those which especially produce antheridia. When- 

 ever rain falls, or there is a heavy dew, a considerable 

 quantity of water trickles down from the patches which 

 bear the antheridia, to those beneath them in which the 

 archegonia occur. Moreover, the quantity of fruit in Frul- 

 lania, however abundant it may be, is not at all proportion- 

 ate to the enormous number of archegonial branches which 

 the plant produces. The greater number of the flowers 

 (which only contain two or three archegonia) are abortive, 

 and produce no fruit. 



The structure of the perianth of the Jungermannise is no 

 obstacle to the impregnation. In Radula, in Frullania, even 

 in the Lejeunise, the development of the rudiments of the 

 fruit commences before the margin of the perianth is raised 

 above the apex of the archegonia. In Jungermannia bicus- 

 jyidata also the development of the fruit often begins very 

 early, when the perianth has still the form of a wide open 

 basket (PI. VIII, fig. 3), but often also (as is the case too 

 with J. divaricata) at a considerably later period, when the 

 perianth has assumed the form of a hollow cylinder, when 

 its margin begins to become folded and to bend inwards. 

 These instances, however, are just those which afford un- 

 doubted proof that even under unfavorable circumstances 

 the spermatozoa can reach the, antheridia. In perianths of 

 both species which I have cut open longitudinally and 

 placed quickly in water, I have several times most clearly 

 seen spermatozoa in rapid motion, whirling actively around 

 the archegonia (PI. VIII, fig. 12). In the Jungermanniae 

 there is found at the aperture of all archegonia which have 



