32 TEXT-BOOK OF FUNGI 



disappear. In some Agarics, more especially in the genus 

 Lactarius, the laticiferous tubes are variously branched, 

 and anastomose freely, and form a differentiated tissue in 

 the stem, but are also present in every part of the fungus. 

 In this genus the quantity of latex present is so abundant 

 that it escapes in the form of drops when a slight wound 

 is made in the flesh. The storage of reserve food is met 

 with most abundantly in sclerotia, but not infrequently 

 certain of the cells in single hyphae become much swollen 

 and thick-walled, and contain reserve food. Such swollen 

 intercalary or terminal cells have more than once been 

 described as the oospores of Saprolegnia and allied forms, 

 when met with in sections of fossil wood. 



4. Reproductive System. Includes those portions 

 directly concerned with the production of reproductive 

 bodies, sporophores, conidiophores, oospores, spores, coni- 

 dia, zoospores, etc. 



In the majority of fungi the entire mass of vegetative 

 hyphae or mycelium must be considered as nutritive in 

 function, as when the mycelium spreads in humus, dead 

 wood, etc., and even in the case of those parasites where 

 the hyphae are intercellular, or run between the cells of 

 the host-plant. On the other hand, in many parasites 

 certain portions only of the mass of vegetative hyphae are 

 concerned with the act of nutrition. In the Perisporiaceae, 

 which are unique in having the vegetative mycelium super- 

 ficial, and forming a more or less evident weft on the 

 surface of the host-plant, certain portions of hyphae that 

 are in direct contact with the surface of a leaf produce a 

 very delicate lateral branch, which pierces the epidermis 

 of the host-plant, and enters an epidermal cell. Inside 

 the cell the slender branch of mycelium, called the neck, 



