48 



PRINCIPLES OF PLANT-TERATOLOGY. 



7 mm. and 6*5 mm. long (fig. 9 b and c). Gyorrfy cites 

 similar cases in the mosses Andresea nivalis (PL Ill, 

 fig 2) and Dicranella varia. There are a few genera 

 of Bryophytes in which forked leaves are a normal 

 feature. 



Under the heading of enlargement and increase of 

 surface of the leaf may be included a phenomenon 

 observed by Potier cle la Varde in the moss Atrichum 

 undulatum. The seta was surrounded and enclosed by 

 a brown organ resembling a sheathing bract, which he 

 considered to be probably a transformed and modified 

 involucral leaf ; the margins of the sheath were united 

 for half its length ; it had no midrib, and occurred at 



a b c 



Fig. 9. — Mnium punctatum. a. Leaf with lamellar outgrowth (I) 

 from dorsal midrib, b and c. Leaves showing unequal dichotomy. 

 (After Arnaoudoff.) 



the base of the paraphyses ; the capsule, perhaps in 

 correlation therewith, was very short and abruptly 

 truncate, and contained only twenty spores (fig. 10). 



Here also may be mentioned those cases which 

 remind us of the laminar enations on the leaves of the 

 higher plants. Limpricht observed a much smaller 

 secondary lamina arising from the midrib of the lower 

 side of the leaf in the moss Phascum brt/oides. In the 

 same wa}^ Arnaoudoff describes a small lamellar out- 

 growth from one side of the midrib of the lower surface 

 of the leaf of the moss Mnium punctatum (fig. 9 a). 



Brizi observed two leaves of the moss Barbula 

 Brebissonii united halfway along the midrib of the 

 lower surfaces, and in Orthotrichum leiocarpum two 

 leaves similarly united by the lower third of their 

 laminae. 



