Dec, 1910.] Self-Dividing Laminae of Cei-tain Kelps. 227 



LITERATURE. 



Kjellman, F. R. Laminariaceae in Pfianzenfaniilien, I, 2. 1893. 

 MacMillan, C. Observations on Nereocystis. Bulletin Torrey 



Botanical Chib, 26. 1899. 

 Oltmanns, F. Morphologie und Biologie der Algen, I. 1904. 



Reinke, J. Studien zur vergleicliende Entwickelungsgeschichte 

 dor Laminariaceen. Kiel. 1903. 



Rosenthal, O. Zur Kenntnis von Macrocystis und Tlialassio- 

 phyllum. Flora 43. 1890. 



Setchell, W. A. Classification and Geographical Distribution 

 of the Laminariaceae. Trans. Connecticut Acad. 9. 1893. 



Skottsberg, C. Zur Kenntnis der Subantartischen und Antar- 

 lischcn Meeresalgen. I. Phaeophyceen. 1907. 



Sykes, Miss M. G. Anatomy and Histology of Macrocystis 

 pyrifera and Laminaria saccharina. Annals of Bot. 22. 1908. 



EXPLANATION OF PLATES. 



A Young Nereocystis plant showing splits and splitting lines. 

 Cross section of Nereocystis lamina at a point corresponding to 



to Fig. 1, a. 

 Cross section of Nereocj'stis lamina at a point near end of split 



corresponding to Fig. 1, b. 

 Cross section of Nereocystis lamina showing mechanical tear. 

 Cross section of a newdy divided lamina of Nereocystis showing 



wounds. 

 Healing lamina of Nereocystis. 

 Healing lamina of Nereocystis, later stage. 

 Completely healed lamina of Nereocystis. 

 Cross section of normal Postelsia lamina. 

 Middle stage in splitting Postelsia lamina. 

 Final stage in splitting lamina of Postelsia. 

 Last stage of splitting in Lessoniopsis. 

 Entire section showing position of Fig. 12. 

 Origin of perforation in Macrocystis, middle stage. 

 vStructure of portion enclosed in dotted line. Fig. 13. 

 Final stage in the development of the original perforation in 



Macrocystis. 

 First stage in the advance of the mature cleft in the Macrocystis 



lamina. 

 Primary cortical meristem in splitting region of Dictj^oneuron. 

 Secondar}^ cortical meristem within the first in Dictyoneuron. 

 The cleft and fan shaped structure developed in the splitting of 



the Dictyoneuron lam.ina. 

 Fig. 20. Final stage in the dividing process in Dictyoneuron. Cortical 



meristem present. 



