288 Kansas Academy of Science. 



These antherozoids are microscopic spiral sperms, provided with two or 

 more long cilia (sensitive muscular flexible hairs) by means of which they 

 propel themselves through the water to the oosphere. 



Fertilization must take place under water, as in a drop of dew or rain, 

 which is usually ample. The oosphere in the archegonial plant, after fecun- 

 dation, becomes an oospore, a globular body analogous to a seed, which, 

 when in a place adapted to its growth, after its period of rest (formative 

 period) is ended, may develop and grow into a spore-bearing plant (a sporo- 

 phyte), as at first. 



There are three general subdivisions of these plants: (a) Those which 

 in the sporophytic stage have solid stems, few highly developed leaves, and 

 a moderately developed sporophore system; in the gametophytic stage they 

 have a very primitive reproductive system (ferns), (b) Those which in the 

 sporophytic stage have tubular jointed stems, rudimentary leaves, and a 

 more complex and highly developed sporophore system; in the gametophytic 

 stage they have a somewhat primitive reproductive system (horsetails), 

 (c) Those which in the sporophytic stage have solid stems, very many mi- 

 nute simple leaves, and a highly developed sporophore system; and in the 

 gametophytic stage have a more highly developed and more occult repro- 

 ductive system (club mosses) . 



Subphylum A. STEREOCAULONES (Filices.) 



Solid-stemmed Pteridophytes. 



A.rchegoniate plants, in which the sporophytes have stems and leaves 

 without large cavities, and in which the closed bundles of fibrovascular 

 tissue are firm and continuous from end to end without articulation, but 

 with the bifurcation necessary to produce increase of surface. 



There are several classes, but only one represented in Kansas, unless 

 Isoetes be regarded as a separate class. 



Class III. PTERIDINE.ffi: (Filicineae) . 

 Fernworts. 



Plants which in the pteral or sporophyte stage have solid horizontal 

 stems, erect sterile and spore-bearing leaves (fronds), and well-developed 

 roots. The fronds are circinate or coiled in prefoliation and usually have 

 dichotomous nervation. In the gametophyte stage the plants are small, 

 flat, green, cellular prothallia, on the under surface of which the fruit- 

 bearing bodies, antheridia and archegonia, are borne; in a few cases the 

 gametophytes are enclosed in small globose bodies (sporocarps) which re- 

 main and develop on the sporophores, thus simulating seeds. 



There are four subclasses, and four orders in Kansas coterminous with 

 them, one order to each subclass, based according to whether the sporangia 

 are developed on the surface of a frond (leptosporangiate) or are deep- 

 seated (eusporangiate) , and according to whether the spores borne by any 

 sporophytic plant are all of one size (homosporous) and the resulting 

 oophores are monoecious; or whether the spores are of two sizes, as micro- 

 spores and megaspores, in which case the sporophores are heterosporous 

 and the resulting oophores are dioecious. These four subclasses cross each 



