242 MORPIIOLOG V. 



what and are somewhat irregular and sotnetimcs divide or branch. They 

 are supposed to represent rudimcntar)' claters. The cells in the other tiers 

 are actual mother-cells, and each one forms four sporcG. 



509. The sporophyte of anthoceros represents the highest type found in 

 the li\-crworls. The spongy green parenchyma forming the wall, with the 

 stomata in the epidermal layer, fits this tissue for the process of photosyn- 

 thesis, so that this part of the sporophyte functions as the green leaf of the 

 seed plants. It has been suggested by some that if the rhizoids on the 

 nourishing foot could only extend outside and anchor in the soil, the sporo- 

 phyte of anthoceros could liye an independent existence. But we see that 

 it stops short of that. 



Classification of the Liverworts. 



CLASS HEPATICE. 



510. Order Marchantiales.* — There are two families represented in 



the United States. 



Family Ricciaceae, including Riccia and Ricciocaryjus. 



Family Marchantiaccse, including Alarchantia, Fegatella (= Cono- 

 cephalus), Fimbriaiia, Targionia, etc. 



511. Order Juugermanniales.* — There are two subdiWsions of this order. 

 The AnacrogyniT include chiefly thalloid forms wdth continued apical 

 growth, the archegonia back of the apical cell. Examples: Blasia, Aneura, 

 Pellia, etc. 



The Acrogyntr include chiefly foliose forms, the archegonia arising from 

 the apical cell and in such cases interrupting apical growth. Examples: 

 Cephalozia, Frullania, Bazzania, Jungcrmannia, Ptilidium, Porella, etc. 



CLASS ANTHOCEROTES. 



512. The Anthocerotes have formerly been placed with the Hepaticas 

 as an order. But because of their wide divergence from the other liver- 

 worts in the development of the se.xual organs, and especially in the struc- 

 ture of the .sporophyte, they are now by some separated as a distinct class. 

 There is one order. 



Order Anthocerotales.* — This includes one family f.\nthocerotacea') 

 with .-\nthoceros and Notothvlas in Europe and North .\merica, and Den- 

 dr(.)ceros in the tropics. The latter is e|Mphytic. 



* As subclass in Engler and Prantl. 



