1 62 MORPHOLOGY. 



APPENDIX. 

 CHARGE 



90. The small group of the Characeos, consisting of the two 

 species Chara and Nitella, which are separated merely on anato- 

 mical grounds, have hitherto presented great difficulties in the way 

 of its classification. It is not improbable that subsequent inves- 

 tigations or discoveries may throw some light upon its proper 

 affinity with other classes. According to our present knowledge, 

 we must, at all events, place it as far from the sexual plants as 

 from the Algae, while we are as yet unable to decide whether it 

 belongs to the Gymnosporee or the Angiosporce. 



Here, again, we suffer from the absence of the necessary investigations, 

 especially with regard to the structural formation of the spores. The 

 inexplicable organs, termed anthers, which it presents, afford an ana- 

 logy, although but a faint one, with structures called antheridias in the 

 Mosses and Liverworts. The differences are, however, numerous and 

 important, and we are, as yet, unacquainted with anything analogous to 

 the structure of the sporocarp. 



91. The spore-cell, which is enclosed by other cells, expands 

 at a certain definite point, issues from its case, and developes in 

 two directions, terminating downward in one or more thread-like 

 adhering fibres, by which it attaches itself, and upward in an 

 utricle of variable length ; from the extremity of this new cells are 

 developed, and there arrange themselves to form the plant.* In 

 Nitella the plant consists of separate cylindrical filamentous cells, 

 arranged end to end ; at the points of union a whorl of similarly 

 united cells is produced, forming lateral branches, which, on the 

 side turned towards the axil, bears small cells, frequently occur- 

 ring in pairs, which are likewise inserted at the junction of two 

 cells of the branch. The same arrangement occurs in the case of 

 Chara, excepting that here a simple layer of elongated cells is 

 spirally wound round the cells of the axis and the lateral branches, 

 forming a kind of cortical layer. In the cells of Nitella and the 

 cortical cells of Chara, the chlorophyll granules are ranged in rows, 

 running spirally round the axis of the cells. 



The structure of the Characece is, as has been described, extremely 

 simple. Much, however, is still wanting in regard to our knowledge of 

 individual points. Meyen's account of the development of the cell of 

 the Charace<B\ scarcely furnishes us with the most superficial informa- 

 tion on the subject ; and, for an investigation of the kind, it would have 

 been far better had he made choice of a germinating Nitella, instead of 



* See the admirable treatise of Kaulfuss upon the germination of the Characece. 

 Leipzig, 1725. [See also a paper on the structure of the Chara, by Mr. Varley. 

 Mic. Trans. TRANS.] 



f Meyen's Physiologic, vol. iii. p. 339, &c. 



