374 OBGANOGKAPHT. 



globule is condensed) considers the spermatozoids of the Charas 

 to be unquestionably of the same nature as those of Mosses and 

 Liverworts. 



The nucule is regarded as a pistillidium or archegonium. It 

 is an oval sessile body, situated 



J^ig. 819. I<ig. 820. -^^ ^|^g ^^-^ ^f ^ ^^^.^^^^1^ ^^^^ 816, 



w) ; it consists of a central sac 

 containing protoplasm, oil, and 

 starch granules {fig. 820), sur- 

 rounded by five cells, which are 

 wound spirally round it, and ter- 

 minating above in five or ten 

 smaller cells, the ends of which 

 remain free {fig. 819, a), and thus 

 form a kind of crown at the apex 



of the nucule. At an early stage 

 Fig.8\9. Nucule of Chara. «. Apices _r- ^i ^\ n ^ j 



of the spirally wound cells.— //£, of growth the cells are separated 

 820. Vertical section of the uucuie from one another, and a canal is 

 thus left between them extending 

 from the crown towards the central cell. This canal is sup- 

 posed to form a passage, by means of which the antherozoids 

 reach the central cell of the nucule, by which it is fertilized. 

 Ultimately the nucule drops off, and germinates in a manner 

 closely resembling the seed of a Monocotyledonous Plant, by 

 which a new plant is formed. No intermediate prothallium is 

 produced. 



Section 2. — Keproductive Organs of Thallogens. 



The Thallogens may be divided into three large groups or 

 orders, called respectively, Lichenes, Fungi, and Algse, each of 

 which again comprises a number of subordinate divisions. The 

 detailed description of these subordinate divisions would be out 

 of place in this manual, but an admirable description of them 

 maybe found in "The Microscope," by Dr. Carpenter. The 

 general characters of the larger groups will be described here- 

 after in Systematic Botany. At present we have only to examine 

 their reproductive organs, and of these even we can only afford 

 space for a general sketch. 



1. Lichenes or Lichens. — The reproductive organs of this 

 lai'ge order of plants are by no means so well understood as 

 those of the Acrogenous Cryptogams already described. From 

 the researches of M. Tulasne and others, it would appear that 

 the reproductive organs of Lichens are of three kinds, namely, 

 1. AjJothecia of various forms, containing a number of spore- 

 cases, called asci or thec(S, and which are supposed to represent the 

 female organs ; 2. 8permogonia, spermagonia, or spermatogonia, 

 ■which have been regarded by some as antheridia or male organs ; 



