CHAR AC E^ 



177 



thallium or 'pro-embryo ' which proceeds from the germinating oosperm. 

 No mode of vegetative propagation is known in the other genera. 



The sexual reproductive organs of the Characeae, the male antherids 

 and the female archegones, are visible to the naked eye as minute orange- 

 red globes and elliptical green bodies springing from the nodes in the 

 axils of leaves or bracts. 

 The antherids are glo- 

 bular bodies, of a bright 

 red colour when mature, 

 from ^ to I mm. in dia- 

 meter, morphologically 

 the terminal cell of a 

 leaf or lateral leaflet. 

 The moderately thick 

 wall of the antherid is 

 made up of eight flat 

 disc-shaped cells called 

 shields, four of which, 

 situated round the distal 

 pole of the l)all. are tri- 

 angular, while the four 

 situated round the base 

 are four-sided. On their 

 inner face there lies 

 a layer of chlorophyll- 

 grains, which eventuallv 

 turn red, while the outer 

 face is clear and trans- 

 parent ; the walls of 

 these cells are folded in- 

 wards at the edge where 

 they meet. From the 

 centre of the inner face 

 of each shield a cylin- 

 drical cell, termed a 

 handle or inaniibrhun, 

 projects inwards nearly to the centre of the globe. The antherid 

 is supported on a short flask-shaped /^'^/V^/-*:^//, which also projects 

 into the interior between the four lower four-sided shields. At the 

 free end of each of the eight manubria is a roundish hyaline cell, the 

 head-cell or capitidum. These twenty-five cells— viz. the eight shields, 

 eight manubria, eight capitula, and the pedicel-cell — constitute the 



Fig. ibi. — Nitella Jlexilis Ag. A, nearly- ripe antherid sub- 

 tended by two bracts showing direction of protoplasm-cunents, 

 and neutral zone. i. ^, manubrium, with capitulum, secondary 

 capitula, and whip-like filaments. C — F, antheiidial filaments, 

 showing formation of antherozoids. G, antherozoids (C— 6^ x 

 550). (After Sachs.) 



