FERNS. 135 



become mucilaginous. The union of an antherozoid with 

 the oosphere is necessary in order to the subsequent devel- 

 opment of the latter.^ 



Minute Anatomy, 



Full instruction for the study of the minute anatomy of 

 ferns is given in a number of accessible manuals, and need 

 not be repeated here. A quite full and satisfactory ac- 

 count of Pteris is given by Sedgwick and Wilson in their 

 Greneral Biology, and Adiantum is well treated by Arthur, 

 Barnes, and Coulter in the Plant Dissection. It appears 

 to the writer better, if the time is limited, to undertake 

 complete examination of only one part, preferably the stem, 

 since the leaf repeats in its general structure much of what 

 has already been seen in the flowering plants. In studying 

 the stem, most of the time should be given to the fibro- 

 vascular bundle, including a comparison of its structure 

 with that of the bundle of Indian corn and the apple tree. 

 The investigation may well be extended to various other 

 plants ; but its success will depend on the preparation and 

 judgment of the teacher, and the previous training of the 

 student. On the whole, a comprehensive study of the 

 fibro-vascular bundle hardly falls within the scope of an 

 elementary course. 



RELATIONSHIP. 



A careful comparative study of a number of prominent 



genera of ferns should be made. Those named above are 



1 Only a bare outline is given above. For further details the student 

 should consult Strasburger, Practical Botany, pp. 290-296 ; Bennett and 

 Murray, Gryptogamic Botany, p. 64 et seq. ; Goebel, Outlines of Classifi- 

 cation and Special Morphology, p. 198 et seq., and references given by the 

 authors just named. For some of the most recent and valuable contri- 

 butions see Campbell, Development of the Ostrich Fern, and various 

 papers by the same author in the Botanical Gazette, Annals of Botany, 

 and other periodicals. 



