392 M. Miiller on the Development of Chara. 



acute (compare § 2), which evidently arises from their having 

 been inserted in the intercellular passages between the nucleus 

 and the spore-sac. In fig. 3 the ripe fruit, the internal membrane 

 of the spore-sac cannot be any longer recognised. From what 

 has been stated the simple deduction arises, that the fruit is the 

 metamorphosed bud of a branch or shoot. Even as regards its 

 function it is nothing more than a bud, which differs from the ter- 

 minal bud of the stem merely in combining at the same time one 

 character of the stem, i. e. the cortical layer. Hence the nucleus 

 is nothing more than the perfect analogue of the central utricle 

 or of the metamorphosed stem itself. The sporal sac is the perfect 

 analogue of the cortical layer of the stem. The contents of the 

 nucleus agree perfectly with those of the internodial cells of Ni- 

 tella. The fruit of Chara differs from these buds only in its com- 

 pound structure. Whilst the buds of the stem and branches were 

 developed longitudinally, the buds destined to form the fruit re- 

 mained at the grade of buds and concentrated their formative 

 powers in themselves. Finally, no impregnation takes place. This 

 deduction is evidently a consequence of the above ; however it 

 can do no harm to mention it again here in italics. Thus all arti- 

 ficial investigations on the so-called anthers are referred to a se- 

 parate province, and their explanation becomes still more obscure. 



The five terminal cells, like the other parts of the sporal sac, have 

 to defend the young nucleus from injury ; they therefore grow to- 

 gether over it and perfectly inclose it. The sporal membrane has 

 to fulfill the same office as soon as the spores are deprived of their 

 coating, the spore-sac, in order to prevent their development into 

 new plants. 



After the above remarks had been written, I found in Kiitzing's 

 ' Phycologia,^ p. 80, a similar comparison of the individual organs 

 of the fruit. I add them here for comparison with my own : ^' The 

 true fruit of the Charm is nothing more than a branch, the evo- 

 lution of which takes place in width instead of in length ; the 

 ^YQ cells which crown its apex are the verticil of branches*. The 

 internal utricle has become transformed into the coats of the seed ; 

 the external tubes, which form the cortical layer in the stem, form 

 the external coat of the seed f ; the angular cell-contents % be- 



* From what has been stated this cannot be true, because branches are 

 never formed from the cortical layer ; we rather have a repetition and a con- 

 firmation of the development of new cortical cells in the older ones beauti- 

 fully repeated in the cortical layer of the stem. Kiitzing regards this cor- 

 tical layer as the elongation downwards of the cells of the branches. Hence 

 the five terminal cells are new cortical cells. 



t Older authors also believed this, as Meyen, Phys. 3 Bd. p. 395, where 

 a similar morphological interpretation of the fruit of the Charce is antici- 

 pated. I hope to have rendered the above extended interpretation useless 

 by direct observations. 



X From what has been stated this is incorrect. 



