5 TUDIES A MONG O UR COMMON HEPA TICyE. 183 



On most stems and branches no rootlets, as a rule, are developed, 

 althoug-h it is occasionally possible to find one or two of them at the 

 base of an underleaf. The place of these important bodies is in part 

 supplied by peculiarly modified branches known as "flagella;" they 

 are much longer and slenderer than ordinary branches and their 

 leaves are either rudimentary or absent altogether. The flagella are 

 sometimes borne on the under surface of a stem just above an under- 

 leaf when they are leafless throughout; but in American specimens 

 at any rate, it is more common to find them in the lateral position, 

 where they start out as ordinary branches but sooner or later cease to 

 develop leaves and acquire their characteristic appearance. On the 

 flagella, rootlets are frequent and are found in clusters where leaves 

 and underleaves would normally be situated. The flagella are of 

 great importance for our plant and give it its power of creeping 

 over tufts of mosses. They are so much firmer than the delicate 

 rootlets that they are able to penetrate deeply into a tuft to hold 

 the stem from which they spring firmly in position and to draw up 

 moisture from below. 



Lepidozia reptans is typically a monoicous species, although it is 

 not unusual to find plants which bear archegonia only. The male 

 and female organs, however, instead of being found on the same 

 stem or branch as was the case in Lophocolea heterophylla, are de- 

 veloped on different branches. Unlike the vegetative branches, 

 those which bear the sexual organs are borne on the under side of the 

 stem just above an underleaf, in the position occasionally occupied by 

 a flagellum. They occur singly, and their pale, bleached-out appear- 

 ance will at once serve to distinguish them. 



Theantheridial branch is curved and small, being about twice the 

 length of the stem-leaves, and it bears about half a dozen closely im- 

 bricated bracts, each of which encloses a single antheridium. The 

 small bracts are very concave and are cleft about one-third into two 

 or three subacute lobes, separated by narrow sinuses ; their cells are 

 very delicate in texture. The bracts are so closely crowded that it is 

 often difficult to demonstrate the underleaves or "perigonial 

 bracteoles." A careful dissection, however, will show that these 

 structures are much smaller and more delicate than ordinary under- 

 leaves, that they are ovate in shape and are cleft about one-third into 

 two subacute lobes. 



The archegonial branch is much larger and more conspicuous 

 than the one just described and bears a perianth 3 or 4'"™- long and 

 I mm. in diameter. The branch is very fleshy and succulent in the lower 

 part and gives off numerous rootlets which help hold it in place. 

 It curves sharply about the stem from which it grows and brings 



