GROWTH OF CELLS. 157 



is LIMITED or UNLIMITED, according as it either ceases at 

 a definite time, or continues as long as the plant lives. 

 Apical growth is limited in all cells, growing at the apex, 

 of many-celled plants, also in many axes of unicellular 

 plants. It is unlimited in particular axes of unicellular 

 plants, as, for instance, in the main axis of Caulerpa, 

 Bryopsis, &c. 



Apical growth is not found in all cells ; it is wanting 

 even in the great majority of cells. I have observed it 

 in unicellular Algae, as Caulerpa, Bryopsis, VaucJieria, 

 Falonia, Codium, Halymeda, Udotea ; in unicellular Fungi, 

 as Achlya, Bremia, Mucor, &c. ; in the terminal cells of 

 many Algae, Florideae, and Fungi, as, for instance, Con- 

 ferva, Dasydadus, Griffithsia, Polyactis, &c. ; in the roots 

 of many Algae, Florideae, and Fungi; in unicellular 

 hairs, or the terminal cells of many-celled hairs, in the 

 pollen-tube \ lastly, in all cells growing out into a branch, 

 as, for instance, in the cells forming the articulations of 

 many Algae, Florideae, Fungi, and the organs consisting 

 of series of cells in the higher plants, moreover in the 

 epidermal cells of the higher and lower plants, &c. 



