CRYPTOGAMS 



305 



with its 

 haulms, 



Fig. 224. — Leocarpus fragllis. 

 Groups of sporangia upon Moss. 

 (Nat. size.) 



reddish-brown oval sporangia, may frequently be found on moss, grass- 

 etc. The sporangia are simple, and have a double peridium and a 

 reticulate filamentous 

 capillitium, but no 

 columella (Fig. 224). 

 Trichia varia, one of 

 the commonest species 

 on decaying wood, has 

 a sessile globose spor- 

 angium with a yellowish 



peridium, which, after rupturing, forms a dish-shaped 

 receptacle. The capillitium is made up of delicate 

 tubes strengthened by spiral thickenings, and having 

 free extremities (Fig. 223). 



A few Slime-Fungi, termed collectively Acrasieae, 

 exhibit a more simple mode of spore-formation. The 

 spores on germination give rise directly to amoebae 

 without the previous development of swarm-spores. 

 The amoebae multiply by division, and without 

 previously undergoing fusion form so-called aggre- 

 gate plasmodia. In the process of spore-formation 

 each amoeba of such aggregate plasmodia surrounds 

 itself with a wall and assumes the nature of a 

 spore. 



Plasnwdiophora Brassicae, one of the few parasitic 

 Myxomycetes, causes tuberous swellings on the lateral 

 roots of various species of Brassica. Its plasmodia 

 fill the cells of the hypertrophied parenchyma of 

 these swellings, and these, eventually dividing into 

 numerous spores, are set free by the disorganisation of 

 the plant. The spores germinate like those of Ohon- 

 drioderma, and the Myxamosbae penetrate the roots 

 of a young Cabbage-plant. The formation of true 

 sporangia, however, does not take place, and this 



Slime-Fungus represents a more simply organised or, in consequence of its parasitic 



mode of life, a degenerate Myxomycete. 



Fig. 223. — Trichia varia. A, 

 Closed and open sporangia 

 ( X 6) ; £, a fibre of the capil- 

 litium ( x 240) ; C, spores ( x 

 240). 



Class II 



Sehizophyta (Fission-Plants) 



The Sehizophyta comprise only Thallophytes, having very simple 

 structure ; they may be either unicellular or filamentous, consisting of 

 a row of cells, or they may assume the form of cell colonies. They have 

 no sexual mode of reproduction, and multiply only by cell division or by 

 asexually-formed spores. They include two orders— the Fission-Algae 

 or Schizophyceae, and the Schizornycetes (Fission-Fungi or Bacteria). The 

 cells of the Schizophyceae contain an assimilating blue -green colour- 

 ing matter. The Schizomycetes, on the other hand, which are only 



X 



