SURVEY OF THE REPRODUCTIVE PROCESS 



tain rudimentary organs are formed the plumule, radicle, 

 and cotyledons, representing the axis, root, and leaves of 

 the future plant and it is on differences in this respect 

 that the great division into Monocotyledons and Dicotyle- 

 dons is based.* 



The whole process of development is more rapid than in 

 the Coniferae, there being no arrest in the growth of the 

 pollen-tube, and the flowering and seeding of the plant 

 being generally accomplished in the same season ; but there 

 is an entire agreement in the main feature the adhesion 

 of the ovule to the parent plant till the maturation of the 

 embryo. In some exceptional cases the connection is not 

 entirely broken off even then ; the inextricable thickets of 

 Mangrove, with which swampy tropical shores are fringed, 

 are said to be due to the property which the seeds of this 

 tree have of germinating while still attached to the branch.*)* 



From this sketch of the reproductive process, it appears 

 that the Angiospermous Phanerogamia differ both from 

 Coniferse and from the higher Cryptogamia (Rhizocarps, 

 Ferns, &c) firstly, in the absence of any accessory cells at 

 the summit of the embryo-sac, like those which form the 

 crown of the corpusculum and the styloid neck of the arche- 

 gonium ; secondly, in the non-development of any distinct 

 tissue in the ovule, like the albuminous body or the 

 prothallium ; in compensation for which, as it were, we 

 have, thirdly, an additional outer envelope the germen or 

 ovary. From the Cryptogamic orders they differ farther in 

 the separation, as it would seem, of the two elements by 

 the continuous membranes of the pollen-tube and embryo- 

 sac. In Phanerogamia we have two distinct genital canals, 

 but neither of them corresponds to the archegonial canal 



* Irf the Orobranchese and Orchidacese, the embryo reaches no higher 

 development, in the ripening of the seed, than a globular mass of cells. 



t In apples, &c., the seeds are sometimes seen in a state of germina- 

 tion. 



