IN THE VEGETABLE KINGDOM. 57 



spore-coats, but by a regular aperture or micropyle, evi- 

 dently corresponding with the perforation so named in the 

 coats of the ovule. No such aperture is required in the 

 lower orders, where the archegonia are either naked as in 

 mosses, or merely sunk in the surface of an exposed pro- 

 thallium as in ferns. The pore going by this name in the 

 sporangial cell of an Alga corresponds rather to the arche- 

 gonial canal, than to the micropyle of these spores, or of 

 true seeds.* 



9. REPRODUCTION IN THE GYMNOSPERMOUS PHANEROGAMIA. 



The group of plants now known as Gymnospermeae, in- 

 cluding the Coniferse and their allies, agree with the other 

 Phanerogamia in the general character of the reproductive 

 process that is to say, the ovules which contain the germi- 

 nal bodies are formed and matured in connection with the 

 parent plant, and are fertilized by the action of pollen 

 grains produced in anthers, which grow on the same or on 

 different individuals, according as the monoecious or dioecious 

 arrangement prevails in the species. At the same time 

 they present some interesting peculiarities, which indicate 

 an approximation to the process as performed in the higher 

 Cryptogamia. The characteristic feature of the fructifica- 

 tion is that the carpels which bear the ovules are not folded 

 so as to enclose them, but merely bear them on their mar- 



* The first discoverers of the prothallial structures of the higher Cryp- 

 togamia were Nageli, Hunter, and Suminski. A notice of the lahr 

 writers is given by Professor Henfrey in the Annals of Natural History, 

 2d Ser., Vol. IX., p. 441. Hofmeister is the best known. An English 

 edition of his works was announced some years ago, but has not yet ap- 

 peared ; it is understood, however, that the Eay Society has it in con- 

 templation. A general survey of the reproduction both of Cryptogamic 

 and Phanerogamic plants is given by Dr. Sanderson in the Cyclop?, da of 

 Anatomy and Physiology, Art. " Vegetable Ovum.," Vol. IV., p. 211. 

 (Part XLV. March, 1855.) 



D 3 



