CRYPTOGAMS 303 



masses of protoplasm, the Plasmodia, containing numerous small nuclei 

 but utterly devoid of chlorophyll. In consequence they are reduced 

 to a saprophytic mode of life upon decaying vegetable remains, or as 

 parasites they often obtain their nourishment from living plants. The 

 Plasmodia (p. 51) are found most frequently in forests, upon soil rich 

 in humus, upon fallen leaves, and in decaying wood. They creep 

 about on the substrata, changing their form at the same time, and 

 thrust out processes or pseudopodia, which may in turn coalesce. 

 Their movements are regulated by the intensity of the light and heat 

 to which they are exposed, and by the amount of moisture and 

 nourishment supplied by the substratum. Although in the vegetative 

 condition the plasmodia are negatively heliotropic and positively 

 hydrotropic, these characteristics become changed when the process of 

 spore-formation begins. The plasmodium then creeps out from, the 

 substratum towards the light and air, and, after coming to rest, is con- 

 verted into single or numerous and closely contiguous fructifications, 

 according to the genus. On the periphery of each fructification an outer 

 envelope or peridium is formed ; while internally the contents of the 

 fructification separate into spores, each of which is provided with a 

 nucleus, and enclosed by an outer wall. The spores thus formed have 

 accordingly an asexual origin. In many genera, part of the internal 

 protoplasm within the SPORANGIUM or spore-receptacle is utilised in 

 the formation of a CAPILLITIUM, consisting of isolated or reticulately 

 united threads or tubes. Upon the maturity of the spores, the peri- 

 dium of the sporangium becomes ruptured, and the spores are dis- 

 persed by the wind. In the case of the genus Ceratiomyxa, the process 

 is somewhat simplified, as the fructification is not enveloped by a 

 peridium, and the spores are produced at the extremities of short 

 stalks. Sexual reproduction is entirely absent in the Myxomy- 

 cetes. 



A good example of the development of the plasmodia from the spores is afforded 

 by Chondrioderma difforme, a Slime-Fungus common on decaying leaves, dung, etc. , 

 upon which it forms small, round, sessile sporangia. The germination of the 

 spores (a, Fig. 52, p. 51) may be easily observed when cultivated in an infusion 

 of Cabbage leaves or other vegetable matter. The spore-wall is ruptured and left 

 empty by the escaping protoplast. After developing a flagellum or cilium as an 

 organ of motion, the protoplast swims about in the water, being converted into a 

 swarm-spore (Fig. 52, e-g), with a cell nucleus in its anterior or ciliated end, and 

 a, contractile vacuole in the posterior end of its body. Eventually the cilium 

 is drawn in, and the swarm -spore becomes transformed into a, Myxamosba 

 (Fungus amceba), which creeps about, and, while undergoing constant alteration in 

 its shape, at the same time it takes up food material by enclosing within its proto- 

 plasmic body small particles of foreign matter. The amoebae have also the 

 capacity of multiplication by division. In conditions unfavourable for their develop- 

 ment they surround themselves with a wall, and as microctsts pass into a 

 state of rest from which, under favourable conditions, they again emerge as 

 swarm-spores. Ultimately a number of the Myxamoebae approach close together 



