4-+ 



Class I. HEPATICAE. 



Protonema much reduced, generally consisting ol a 

 short and simple thread only. Plants either thallus-like 

 (frondose) or consisting of stem and leaves (foliose). Stem 

 bilateral, in the foliose groups often with two rows of 

 upper leaves and one row of ventral leaves (amphigastria) 

 (Figs. 40 and 41 F). The leaves generally consist of one layer 

 of cells only, but the fronds of Marchantia and some 

 others are fleshy and provided with stomata and intercellular 

 spaces. 



F"'g. 39- 



Fig. 38. Anthoceros laevis L. sp. Sporogone. <". Columella. Nat. size. 



Fig. 39. Plagioch'ila asplenioides (Vaill.) Dum. s. Sporogone. 



Fig. 40. Frullan'ia Tamarkci (L.) Dum. 36/1. Seen from below. /'. Lateral leaf. 

 ws. Modified lower lobe of leaf (water storing). a. Amphigastrium. (From 

 Strasburger, Textbook) 



The archegonia are either terminal at the end of the 

 stem or the branches, or dorsal, while the antheridia are 

 rarely terminal. The sporogone remains enclosed in the 

 archegonium until nearly fully developed, when, in most 

 cases, it perforates the apex of the archegonia] wall, being 

 raised by the rapid lengthening of its stalk, while the 

 archegonial wall remains at its base as a sheath (Fig. 39). 

 The inner portion of the sporogone produces spores as 

 well as, in most cases, sterile cells, termed elaters, which 



