SPORES. 

 Fig. 686. 



[ 606 ] 



Fig. 687. 



SPORES. 



Fig. 688, 



Pellia epiphylla. Preissia commutata. Blasia pusills 



Spores of Hepaticacese germinating. Magnified 200 diameters. 



here, nor apparently any archegonia. The 

 globule (figs. 125-6, p. 134) produces an- 

 theridia giving birth to spermatozoids. The 

 nucule (fig. 124, p. 133) appears to be a 

 spore (see CHARACE^E). 



In the Lichens only one kind of organ 

 has been termed a spore, namely the repro- 

 ductive cells formed in the thecae (PI. 29. 

 figs. 6 82 12), which are known to reproduce 

 the plant when thrown off by the parent. 

 Two other kinds of body connected with the 

 reproduction do occur ; these, the gonidia\(Pl. 

 29. figs. 2, 3) and the spermatia (see LI- 

 CHENS), have fortunately obtained and pre- 

 served distinctive appellations. The spores 

 are simple cells or septate tubes with a dou- 

 ble membrane. 



In the Algae much confusion still exists, 

 not only between different kinds of spore, 

 but even between spores and sporanges ; 

 and this is not easily cleared away, since in 

 certain cases the organs appear really capable 

 of serving as one or the other, according to 

 circumstances; the true spores are always 

 simple cells with a double or triple coat. 



In the Florideae, the characters of the 

 structures seem pretty clear : we find spores 

 (fig. 698. p. 609), TETRASPORES (figs. 252-4, 

 p. 266) which appear to represent the go- 

 nidia of the Lichens, and spermatozoids (see 

 FLORIDE^E). Among the olive-coloured 



sea-weeds (Fucoids), the FUCACE^B and 

 DICTYOTACE^E produce spores and sper- 

 matozoids ; but in the majority of the fami- 

 lies only a totally different mode of repro- 

 duction is known. The plants produce ovate 

 sacs (commonly called spores) and chambered 

 filaments ; from both are discharged actively 

 moving ciliated cells, corresponding exactly 

 to the ZOOSPORES of the Confervoids. 

 Thuret now regards the oosporanges and 

 trichosporanges (fig. 462, p. 424), as he calls 

 these sacs and filaments respectively, as 

 merely different forms of one kind of struc- 

 ture. But it seems possible that true spores 

 may be discovered; even indeed that the 

 oosporanges may be sometimes parent-cells 

 of zoospores and sometimes spores. 



In the Confervoids we find true spores in 

 very many cases, produced generally after 

 some process of fertilization or of CONJU- 

 GATION, in special cells (fig. 673, and PI. 5. 

 figs. 16 & 18; PI. 6. figs. 1-5). But the 

 " spores" thus produced, while they some- 

 times germinate into new filaments, also 

 sometimes produce numerous bodies of dif- 

 ferent kind, connected in some way with 

 reproduction ; this is the case in SPIROGYRA 

 (PI. 5. fig. 23), perhaps also in CLOSTERIUM 

 and other instances. Besides the spores pro- 

 per, we have also in this family ZOOSPORES, 

 the actively moving ciliated bodies which are 



