376 



ORGANOGRAPHY. 



They are frequently beautifully coloured, and form splendid 

 objects under the microscope. 



In a very few genera of Lichens, as AhrotJiallus and Scutula, 

 certain structures have been discovered by Tulasne, called stylo- 

 spores. These are analogous to the stylospores of certain Fungi. 

 "They consist of isolated spores borne upon shortish simple 

 stalks. They are produced in conceptacles to which is applied 

 the name of ^>?/cwjVZirt," 



The spermago7iia or spermatogonia were first discovered by 

 Tulasne, but they have been now found in a great number of 

 Ijichens, and jorobably exist in all. They generally appiear as 

 little black specks near the margins of the thallus, in the tissue 

 of which they are usually more or less imbedded (Jig. 822, sp) ; 

 but rarely, they are quite free and above the thallus. The sper- 

 raagonium varies in form, and has one or more cavities, with a 

 small orifice at the top termed the ostiole or pore (Jig. 825, os), 

 with M'hich all the cavities communicate. The spermagonium, 

 when mature, has its interior filled with a number of bodies 

 called spcrmatia {figs. 825, s, and 826, s), raised on stalks, 

 termed spermatophorcs {figs. 825, sp, and 826, sp). The form 



Fig. 825. 



Oi 



Fig. 826. 





Fig. 825. Vertical section of a 

 Bperniiigouiuin of Cladonia 

 rangiferina. sp. Siicrmato- 

 phores. os. Ostiole or pore, 

 from which the siieniatia, 

 *, are escaping. After Hen- 



frey. i"/;/. 826. Highly iiiag- 



iiitled fratjiiuiitfrom the wall 



of a speriiiHLroiiiuin of ParmeHa parietina. 



phores. s. Speniiatia. After Henfrey. 



sp. Articulated spermato- 



of the spermatophorcs varies much ; according to Henfrey, " The 

 simplest are short slender stalks, simple or branched; or they 

 are articulated branches composed of a great number of cy- 

 lindroid or globular cells {fig. 826, sp) ; or the branches are 



