_ 4 — 

 2. HISTORICAL. 



The first record of the formation of protonema by the 

 leaves is by Kützing, 1 for Bryum pseudotriquetrum. The 

 leaves produced an abundant protonema growth and after a 

 period of eight weeks, buds appeared. 



Schimper 2 obtained a growth from the basal portion 

 of detached leaves of Funaria hygrometrica, but no buds 

 were produced. He also makes the very broad statement: 

 "Chaque feuille et meme chaque portion de feuille detachee 

 de la plante-mere et placee dans les conditions coovenables 

 peut produire des filaments proembryonnaires, par la multi- 

 plication d'une ou de pleuiseurs de ses cellules parenchyma- 

 tuses." Goebei 3 also mentions the ability of Funaria leaves 

 to produce protonema, when they are detached and kept 

 moist. Limpricht* states that almost every leaf can by 

 proper culture be made to form secondary protonema. Also 

 in the case of plants with brittle leaves as, Leucobryum glau- 

 cum, Barbula fragilis, Campylopus fragilis, and Barbula rura- 

 lis, one can find in nature on the detached leaves the begen- 

 nings of protonema filaments. 



It is to be noted that in all of the cases above men- 

 tioned, regeneration only occurred when the leaves were de- 

 tached from the stem. That this is not necessary in all cases 

 is shown by the observations of Goebei 5 on the leaves 

 of several species. In Oncophorous glaucus a thick feit of 

 tangled filaments appears on the fertile summits of the plants, 

 which prevents their further growth and eventually gives rise 

 to patches of young plants. The marginal cells of Buxbaumia 

 aphylla leaves are able to produce protonema which will 

 completery envelop the leaf. According to Limpricht, 6 the apex 



1 Phycologia generalis p. 282. 1840. 



2 Recherches anatomique et morphologique sur les mousses, 

 p. 19. 1848. 



3 Sitz.-Ber. d. rnat.-phys. Classe d. k. bayr. Akad. d. Wiss. 

 26 : 463. 1896. 



. 4 and 6 Laubmoose von Deutschland 1 : 64. 

 5 Outlines of Classification p. 173. 1887. 



