698 



THE SUBDIVISIONS OF THE VEGETABLE KINGDOM. 



Anthocerotacece. — The oophyte has the form of a little lobed disc, in depres- 

 sions of the surface of which the antheridia and arehegonia are sunk. The sporo- 

 gonium is long and cylindrical, and is invested in a circular sheath at its base. The 

 spore-layer has the form of a hollow cylinder, leaving a sterile, central strand of 

 tissue (the columella). Elaters are present amongst the spores, and serve as 

 nutritive tissue for them rather than as instruments of dispersal. Tn this group 



^^ li\ 



Fig. 396, — JungermanniaceEe. 



* Frullania dilatata growing on the bark of an Acer. - A small portion of tliis plant enlarged ; it shows the stalked spore- 

 capsule burst into four valves ; attached to the valves are the elaters. 8 A shoot of the same FniUania seen from the 

 under side ; at the base of each leaf is a little pitcher containing a Rotifer. The little toothed scales lying on the stem are 

 the aniphig.a3tria. * A single pitcher and its contained Kotifer. * The Rotifer (Callidiua symbiotica) removed from tiie 

 pitcher. inat.size; 2x20; 8x26; »x30; 'xlOO. 



— alone amongst the Liverworts — stomates occur upon the spore-capsule. It 

 dehisces into two valves. 



There are 103 species. 



Jungermanniacece. — Include both thalloid forms, in which the oophyte genei-a- 

 tion has a general resemblance to that of a Marchantia, and creeping leafy forms 

 (cf. fig. 396 ') ; the latter are by far the more numerous. The sporogonium in both 

 cases consists of a long-stalked capsule which splits into four valves (fig. 396 ^). 

 Elaters are present, often attached to the capsule-wall. The Jungermanniacese 

 grow for the most part on damp earth, stones, and bark of trees. 



The thalloid forms include the very common Pellia — like a Marchantia, with 



