CRYPTOGAMS 183 



(4) Reproduction luith conjugation,'^ in the Algpe and other low 

 plants, is often associated with exposure of the plant to adverse con- 

 ditions, such as the approach of winter or drought or the old age of 

 the plant. It seems to be a mode of reinvigorating the species at the 

 moment when the production of a new plant is to be provided for. 

 It is clearly of the same nature as the fertilization of the egg cell in 

 the ovule of the Flowering Plants. 



Reproduction icith conjugation {sexual reproductioii) in the Thallo- 

 phytes is of three types, as indicated above ; viz., 1) zygosporic, 

 2) oosporic, 3) carposporic. An important system of classification of 

 both Algae and Fungi (in which essentially the same reproductive pro- 

 cesses occur as in Alg?e) is founded upon these types. 



FUNGI 



438. Fungi may conveniently be defined as Thallo- 

 phytes lacking chlorophyll. In structure and life habit 

 many of them closely resemble certain AlgtC. In some 

 instances the resemblance is so striking that Ave may with 

 assurance regard the fungal forms, in these cases, as having 

 been derived from Algse, chlorophyll having been lost 

 through the adoption of a parasitic or saprophytic mode 

 of life. Parallel cases in Flowering Plants are furnished 

 by the Dodder (a parasite. Fig. 32) and the Indian Pipe 

 (a saprophyte, § 59). 



439. Many of the species are unicel]ular and very 

 minute. When of more than one cell, the plant body is 

 generally filamentous. Even in the compact, fleshy forms, 

 like the Toadstools, the solid structures are built up of 

 an immense number of essentially independent threads. 

 The vegetative filaments of Fungi are termed hyphce ; 

 and the plant body composed of hyphse (aside from special 

 spore-bearing parts) is the mycelium. 



440. The number of species of Fungi is very great, 

 and the tj^pes are extremely various. A few common 

 forms will be described in order, thereby, to present sev- 

 eral of the most important groups. 



1 These two methods of reproduction are also termed the asexual and 

 the sexual modes, respectively. 



