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American species will be treated, those who follow the series will 



have a very interesting set of specimens at the end. All who wish 



specimens and are not subscribers should subscribe now. 



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A friend of the Fern Bulletin has taken the editor to task 

 for some statements on page 28 of the current volume, in which 

 the reproduction of the fern is described. It is also charged that 

 the position taken in comparing ferns and the higher plants upon 

 the basis of the alternation of generations is untenable. In refer- 

 ence to the latter, it may be said that although both ferns and the 

 higher plants go through a prothallium stage in the processes of 

 reproduction, it is only in the ferns and the lower orders that the 

 prothallium is at all conspicuous, forming two generations or 

 forms of the same plant, and it was in this sense only that the 

 term "alternation of generations" was used. The seed is the 

 resting stage of the plant and really contains a plant in embryo ; 

 the spore is usually the resting stage of the fern, but is not of a 

 similar nature and neither contains a plant embryo nor has the 

 power to directly reproduce one. Between the spore and the 

 "fern," so-called, there exists the prothallium bearing the sex or- 

 gans and often quite conspicuous. As to the likening of these 

 sex organs to the stamens and pistils of higher plants, to which 

 objection is made, the editor emphatically disclaims any idea of 

 intimating that they are homologous. Our discussion did not in- 

 clude a close study of the method of reproduction, and it was 

 wished merely to indicate in a general way the relationship of the 

 sex organs of the ferns to those of higher plants. It may be well, 

 however, to give a short account of the exact method of reproduc- 

 tion in each, in order to correct any misunderstanding that may 

 have arisen, and incidentally to throw more light on the subject of 

 the alternation of generations. If, then, we take some such fern- 

 wort as Selaginella, We shall find that it produces spores of two 

 sizes, the smaller, called micro-spores, producing prothallia bear- 

 ing the male sex organs; and the larger, called macro-spores, 

 producing prothallia bearing the female sex organs. In the 

 higher plants, the anther contains the micro-spores (or pollen 

 grains), and these, falling on the pistil, germinate, forming male 

 prothallia. The pistil contains the macrosporangia (ovules), and 

 each ovule or macrosporangium normally contains one macrospore, 

 which by cell division forms the female prothallium. The pro- 

 thallium of a fern, then, might be compared to a flower, inasmuch 



