CHARAGEu^. 



331 



Carolina tliirty-eiglit edible species o( Agaricus, eleven of Boletus, nine 

 cf Polyporus, seven of Hydnum, and thirteen of Glavaria. 



(/) Polyporites Bowmani of the Carboniferous is the oldest known 

 member of this order. In the Tertiary the modern genera Lenzites, 

 Polyporus, and Hydnum are represented. 



V. Class Chaeace^. 



430. — In this small group of chlorophyll-bearing aquatic 

 plants the sexual organs, while still preserving essentially 

 the structure common to other Carposporeae, present con- 

 siderable modifications. The female organ consists of a 

 "central cell" or carpogonium (Fig. 337, c), which is the 

 terminal one of a row of cells {a, 

 h, c, Fig. 237). From the basal 

 cells there grow out five elongat- 

 ed cells {d, d, Fig. 337), which 

 take an upward direction and 

 surround the carpogonium ; they 

 cohere laterally, so as to forma 

 complete covering. The top of 

 this enveloping sheath becomes 

 modified into a projecting crown 



of five (or by division ten) more lii'^t^T^oi^' ^rttfit 

 or less divergent cells {i, i, Fig. lY.?5,'LS?'l'.?,!'_ '*•„<'.•. '■'_"^l°'«°""y 

 337 B; and c, Fig. 338, A). 

 Finally, the whole envelope be- 

 comes twisted, so that each en- 

 veloping cell passes spirally around the carpogonium {A, 

 Fig. 338). 



431. — The male organ, or antheridium, consists of a 

 globular body composed externally of eight spherically tri- 

 angular cells, called the shields, which are united by their 

 zigzag margins {a, Fig. 338, A). From the centre of each 

 shield there projects into the cavity of the antheridium a 

 cylindrical cell {manulrium), and upon each of these there 

 are borne large numbers (twenty to twenty-five) of long 

 coiled and bent many-celled filaments {h and c. Fig. 339). 

 Each filament contains from one to two hundred cells. 



Fig. 327,— Development of the 

 carpognuium of MteUa Jlexllis, 

 shown in vertical Bection, partly dia- 

 gramtnatic. A, very early i-tage ; 



enveloping cells. B, the same.«ome- 

 what later— the enveloping ceils, 

 d, d, Iiave.'alnioet completely en- 

 closed the central cell, c ; i. i, cells 

 which form a crown upon the en- 

 veloping cells. X 300.— After Sachs. 



