NOTEWORTHY LEJEUNEAE FROM FLORIDA I47 



serving as organs of vegetative reproduction. Such leaves and 

 branches are unknown in Brachiolejeunea but are found in the South 

 American P. torulosus (Lehm. & Lindenb.) Trevis.,^ as understood 

 by Spruce, although their true significance has been overlooked. 



Vegetative reproduction by means of leaves which become sepa- 

 rated and which afterwards give rise to new shoots by a process of 

 regeneration are now known in several genera of the Hepaticae. In 

 most cases the deciduous leaves are essentially like ordinary leaves and 

 the line of separation is irregular. Such leaves are "Bruchblatter," 

 according to the definition of Correns.® In rarer cases the leaves are 

 distinctly modified and separate by means of a regular and definite 

 line. Such leaves are "Brutblatter." Examples of the latter have 

 been described by the writer in Rectolejeunea flagelliformis Evans and 

 R. Berteroana (Gottsche) Evans,' and their occurrence has been noted 

 in Fndlania Bolanderi Aust.^ 



The caducous leaves of Ptychocoleus heterophyllus are likewise 

 Brutblatter. Although they show the usual differentiation into lobe 

 and lobule, both are greatly reduced in size, the lobe measuring about 

 0.25x0.2 mm. and the lobule 0.14x0.09 mm. The latter is further 

 distinguished by bearing only one or two marginal teeth, not inflexed 

 as on ordinary leaves. The separation takes place at the very base 

 and no cells are torn across in the process. After separation the basal 

 cells project as minute crenulations. 



The branches which bear the caducous leaves vary greatly in 

 length but their growth is limited sooner or later, and no evidence is 

 at hand that they ever revert to the typical vegetative condition. In 

 one case thirty pairs of leaves had been produced. The transition 

 between ordinary leaves and caducous leaves is abrupt; as soon as 

 the latter begin to be formed the branch curves away from the sub- 

 stratum and ceases to form rhizoids. The persistent underleaves are 

 much like ordinary underleaves and their reduction in size is less 

 marked than in the case of the leaves. They are very densely crowded, 

 however, and are distinguished also by being squarrose and more or 



5 In his Species Hepaticarum (5: 37. 1912) Stephani cites the present writer 

 as authority for this combination with the reference, "Torr. Bot. CI., 1908, p. 165." 

 If this reference is consulted it will be seen that the combination is correctly assigned 

 to Trevisan. 



•> Unters. iiber die Vermehrung der Laubm. 338. 1899. 



' Bull. Torrey Club 33: 10, 13. 1906. 



8 Bryologist 18: 88. 1915. 



