400 



BOTANY 



a number of unicellular, flask-shaped antheridia (D, an) from \\liii-li naked 

 spherical spermatia without cilia are shed. The lower cell divides into four 

 (D, a, b, c, d), and the cell a projects and gives rise to the multicellular female 

 organ. The true egg-cell (E, ac), which is called the carpogoiiium. is surrounded 

 by a layer of cells. Above the carpogonium come two cells (E, tp, t) the upper of 

 which is the freely projecting trichogyne or receptive organ for the spennatia. 

 The behaviour of the nuclei has not yet been followed, but probably a fusion of 

 male and female nuclei takes place in the carpogonium. The latter becomes 

 divided into three cells of which the uppermost disappears, the lowest (F, st) 

 remains sterile, while from the middle cell the asci grow out. Each ascus ((/) 

 produces four spindle-shaped, bicellular spores. The similarity of the sexual 

 organs to those of the Florideae and of the lichen-forming Ascomycetes is of great 

 interest. 



Sub-Class II. Basidiomycetes ( 



48. 49. 70. 71- 72 



The large group of the Basidiomycetes in the wide sense consists 

 of Fungi, the mycelium of which is septate as in the Ascomycetes, but 



Flo. 343. AriiiiHin-iii uniltti. .1, Yonii.^ 

 Uisidiuin with the two primary 

 nuclei ; B, after fusion of the two 

 nuclei. Hypholomn /'/" '"'" "la-turn, 

 C, a liasidinm before the four nuclei 

 derived from the secondary nucleus 

 of the basidium have passed into the 

 four iKisidiospores ; 1). passage of a 

 nucleus through the sterigma into 

 the liasidiospore. (After RUHLAXD.) 



Kl(i. :i44.--Uasi.lin. .1. Of a rrcdineoiis 

 fungus (EiKlii/ihiillinti I-'.HI i/i M ;'.' 



. i.aftei-Tri.AsxE). /:>', Of one of the 

 Treniellineae (Trrmelln lnti'*>; HX) (after 

 HKEKKI.HX (x 450. From v. TAVEI,, 



is distinguished by the loss of sexual reproduction and by the 

 formation of basidia (p. 388), different forms of which are met with. 

 In the orders Uredineae and Auricularieae the upper portion of 

 the basidium is divided by transverse walls into four cells ; each cell 

 bears on a thin stalk (sterigma), arising near the upper end, a single 

 spore (Fig. 344 A}. In the Treniellineae, on the other hand, the 

 basidium is divided by longitudinal walls into four cells, each of 

 which continues into a long tubular sterigma (Fig. 344 B). The 



