ORGANS OF EEPRODUCTION. 



381 



spiral fibres in their interior, and are much simpler in their 

 structure than those previously described. In Riccia the spo- 

 rangia are imbedded in the substance of the frond, and have 

 neither elaters nor columella. They have no regular dehiscence. 



The spores have usually two coats, like pollen-grains ; the 

 outer coat also frequently presents markings of diiferent kinds : 

 in Marchantia however, the spore has but one coat. They 

 all germinate without any well-marked intermediate pro-thallus, 

 although some produce a sort of confervoid mass or mycelium. 



7. Charace^ or Charas. — There is still much difference 

 of opinion among botanists as to the position of this order. 

 The Charas have been commonly placed among the Algae ; 

 but the structure of their reproductive organs indicates for 

 them a higher position. They are generally considered as 

 intermediate in their nature between Hepaticaceae and Algse, 

 while by Berkley, whose opinions on all matters connected with 

 Cryptogamous Plants are eminently worthy of consideration, 

 they have been classed with the Acrogens ; and, in accordance 

 with his views, we have also placed them in that division of the 

 Cryptogamous Plants. 



The reproductive organs are of two kinds, both of which grow 

 at the bases of the branches (^fig. 813), and either on the same 

 or on different branches of the same plant, or on different plants. 

 These organs are called respectively, the globule (^jig. 813, g\ 

 and the nucule {fig. 813, ri). 



The globule, which is regarded as an antheridium, is a globular 

 body (^^. 813, 5r), of a deep brick-red colour, usually placed 

 immediately below, or occasionally on the side of the nucule. 

 It consists of eight valves, each of which is composed of a 



Fig. 813. 



Fig. 814. 



Fig. 815. 



Fig. 813. A portion of the ajds of CJiara, with nucule, n, arising from the axil of a 



branch, and a globule, g, below it Fig. 814. A portion of a filament,^, oi 



fg. 815, with a ciliated spermatozoid or antherozoid by its side Fig. 815. A 



globule cut in half, to show the oblong cells, c, and the septate filaments, Jil. After 

 Henfrey. 



