288 



THE BRYOPHYTES 



290. The Anthoceros group. These types (order Anthocero- 

 tales) are considered the highest of the liverworts because of 

 their more complicated sporophytes. The gametophytes are thal- 

 loid (Fig. 257), somewhat irregular in outline, and more simple 

 in structure than those of Marchantia. The sporophytes are an 

 inch or more in height, and grow up from the gametophyte like 

 blades of grass. The upper portion splits lengthwise into halves 

 at maturity. 



The spores of Anthoceros do not all mature at once, as in other 

 liverworts, but new spores are formed at the base of the sporo- 

 phyte as the older mature (Fig. 258, A), 

 and there is a continuous elongation of 

 the structure during the summer from a 

 basal region of growth. The cells com- 

 posing the wall of this long sporophyte 

 contain large single chromatophores (Fig. 

 258, jE"), and there are breathing pores, 

 or stomata (singular, stoma, meaning a 

 mouth), on the surface (Fig. 258, Z)), which 

 lead into intercellular spaces in the green 

 tissue beneath. Consequently the sporo- 

 phyte is able to manufacture its own food 

 The thaiioid sexual plants ty photosynthesis, as any green plant may 



(gametophytes), with the / r J 



sporophytes s in various do. But it depends upon the gametophyte 

 stages of development for itg supp iy o f water, which is absorbed 



through a large bulbous foot (Fig. 258, A) that is deeply im- 

 bedded in the thallus of the gametophyte. 



If the base of this sporophyte could establish a root-like 

 structure growing in the soil, it might live independently of the 

 parent gametophyte, for it has chlorophyll-bearing tissues in 

 communication with the air through stomata, just as in the 

 ferns and seed plants. And it has also the power of indefi- 

 nite growth from its basal region (Fig. 258, A], limited only by 

 the length of the summer season. These peculiarities of the 

 sporophyte of Anthoceros are very suggestive of the way in 



FIG. 257. Habit sketch 

 of Anthoceros 



