412 SYSTEMATIC BOTANY. 



is slight, and it has been found necessary to adopt for it the 

 term pseudo-parenchyme. The structure and growth of the fungal 

 cell agree in essential points with those of the vegetable cell as it 

 occurs elsewhere. In the numerous Fungi which develop rapidly 

 and have a short existence in the adult state, the cell-wall is thin, 

 tender, and structureless. The possession of a thick cell-wall of a 

 homogeneous, unstratified nature is not uncommon. Cases also 

 occur (in the Polyporei, Thelephora, Bovista, Geaster, Tulostoma, 

 &c.) in which, by the aid of sulphuric acid, solution of potash, or of 

 Schultz's mixture, a cell-wall of two or more coats is found, but 

 in certain instances simple immersion in water is sufficient to show 

 a beautiful stratification. From the differences in chemical reaction 

 the cell-membrane of Eungi cannot be called true cellulose, and it 

 has therefore received the special name of fungal cellulose. The 

 protoplasm differs from that of the higher plants in the constant 

 absence of chlorophyll and of a nucleus. l)rops of oil and other 

 bodies have occasionally been taken for nuclei, by Schacht, for ex- 

 ample, who also described nuclei of such infinite minuteness that 

 they could not be accepted. In the formation of vacuoles and the 

 possession of fatty oils, both forms of protoplasm agree. JStarch 

 and chlorophyll are always absent, but pigments of various colours 

 occur plentifully. Crystals of calcium oxalate are to be met with 

 in the intercellular spaces of many Eungi, but in only two cases 

 have they been found in the interior of the cell (Russula adusta 

 and Phallus caninus). Cell-division takes place in the same way 

 as in the other plants. 



The reproduction of Eungi is effected by both sexual and asexual 

 means, and the organs by which this is accomplished are in both 

 cases simple cells. No one species is known to possess more than 

 one method of sexual reproduction, though various asexual methods 

 are known to occur in the same species. The organs are called by 

 different names in the different groups, and a description of them 

 will be found under those divisions to which they are peculiar. 



Spores. The term spore is used to signify a reproductive body 

 in a general sense, and for the mother cells from which the spores 

 are developed the word sporangium is employed. It must be men- 

 tioned that, from the very varied modes of reproduction which are 

 met with, a great number of special terms have been proposed in 

 the use of which a certain amount of confusion for some time 

 existed. The spore may be enclosed by one or more coats of dif- 

 ferent degrees of thickness and density. When it germinates, a 

 tube called a germ-tube is emitted, which conducts itself in different 

 ways according to its species. The spore in some instances bursts 

 and produces a number of ciliated spores called swarm-spores or 

 zoospores, which also behave in different ways. The germination of 



