OUR NATIVE PTERIDOPHYTES. 



PTERIDOPHYTA Cohn. 



Plants containing vascular tissue and manifesting two distinct 

 phases in their life-history: (i) An asexual phase (sporophyte) 

 differentiated into stem and leaves, producing spores and de- 

 veloping vascular tissue in bundles throughout their stems and 

 leaves ; and (2) A sexual phase (garnet op hyte) developed from 

 the germination of the spore in the form of a cellular thallus 

 (prothalliuni) on which the sexual organs antheridia and arche- 

 gonia are produced ; from the egg of the archegonium fertilized 

 by the antherozoids from the antheridia arises the asexual 

 phase from which the characters used in classification are 

 largely drawn. Besides several groups that have become extinct 

 the Pteridophytes are represented by three orders : I. FILICALES, 

 containing the ferns and waterworts ; II. EQUISETALES (see 

 p. 126 ) including the horsetails and scouring rushes; and 

 III. LYCOPODIALES (see p. 130), containing the ground-pines 

 and quillworts. 



SYNOPSIS OF THE ORDER FILICALES. 

 (FAMILIES.) 



1. Spores uniform, of one sort 3 



Spores of two sorts (minute microspores and large macrpspores) ... 6 



2. Sporangia rising from the tissues beneath the epidermis (eusporangiate), 



borne in spikes or panicles ; vernation straight or inclined. 



Family i. OPHlOGLOSSACEjE, p. 66 



Sporangia rising from the epidermal cells (leptosporangiate), borne on the 

 back or margin of a leaf (frond) or rarely in panicles ; vernation circi- 

 nate 3 



3. Sporangia sessile, with a complete ring borne on a thread-like receptacle 



from a cup-like involucre ; texture filmy. 



Family 2. HYMENOPHYLLACE^E, p. 74 

 Sporangia borne on the back or margin of the leaf or in spikes or panicles. 4 



4. Plants terrestrial 5 



Plants aquatic ; sporangia sessile, scattered, in a specially folded leaf. 



Family 5. CERATOPTERIDACE^E, p. 78 



5. Sporangia sessile, ovate, with an apical ring, opening longitudinally, mostly 



in panicles or solitary under a scale. . Family 3. SCHIZ^ACE^:, p. 75 



