424 



BOTANY 



PART II 



eight groups of endogenously-formed antheridia and must on this 

 account be termed an antheridiophore. 



The female organ (Fig. 3G4, oh) consists of an oogonium which 

 contains a single egg-cell with nimierous oil-drops and starch grains. 

 To begin with the oogonium projects freely, but later becomes sur- 

 rounded by five spirally wound cells. These cells end in the corona, 

 between the cells of which the spermatozoids make their way in 



Fio. 304. — Chara fragilis. .^, nipdiaii longitiulinal .section througli a lateral axis r, and the .sexual 

 organs whicli it bears (x 00); a, antheridium borne on the basal nodal cell na, by the stalk 

 cell p; 111, manubrium; oh, an oogonium; no, nodal cell; po, the stalk-cell; v, pivotal cell 

 (Wendmigszelle) ; r, the crown. B, a lateral axi.s bearing axes of the third order ( x 6) ; a, 

 antheridium ; o, oogonium. 



fertilisation. At the base of the oogonium there are small cells 

 (Wendungszellen) cut off from the cell-forming oogonial rudiment ; in 

 Chara there is one, in NitcJla three such cells. These divisions corre- 

 spond to the first divisions in the mother-cell of the male organ. The 

 female organ may thus be regarded as an oogoniophore reduced to a 

 single oogonium. 



The egg, after fertilisation, now converted into an oospore, becomes invested 

 with a thick colourless wall. The inner walls of the tubes become thickened 

 and encrusted with a deposit of calcium carbonate, while the external walls of 

 the tubes, soon after the IVuit has been shed, become disintegrated. 



The oospore, on germination, gives rise first to a simple, iilanientous row of 



