THE HIGHER CRYPTOGAMIA. 197 



vation of such archegonia, and the comparison of them Avith 

 those placed farther backwards and having perfect necks, 

 seems to have led Lesczyc-Suminski, and after him Merck- 

 lin, to the erroneous conclusion, that the archegonium in 

 its earliest youth was a short canal opening upon the under 

 side of the prothallium, and that the neck was formed by 

 repeated division, in a direction parallel to the surface of 

 the prothallium, of the cells surrounding the mouth of that 

 canal. 



The abortive prothallia of Nothochlsena, Allosurus, and 

 Gymnogramma calomelanos often exhibit shoots. The ar- 

 rangement of the cells of the prothallium of ferns generally 

 resembles that of the leaf-like shoots of Pellia, Riccia, and 

 Marchantia. It might be supposed from this that a new 

 shoot would originate at the bottom of the notch of the 

 fore edge, and that new shoots again would arise in the 

 axils which the last-mentioned shoot would form with the 

 side wings of the fore edge. This, however, is rarely the 

 case (PI. XVIII, fig. 1). Usually several of the cells of the 

 edge of the prothallium grow into adventitious shoots, which 

 generally have the shape of a large spatula. The activity 

 of the multiplication of their cells breadthwise is ex- 

 ceedingly various. Very slender adventitious shoots 

 with unicellular bases often become detached from their 

 prothallia at an early period by the death and disso- 

 lution of the cells attached to them. They then represent 

 independent, very small prothallia (PI. XXIV, fig. 4), and 

 often bear very numerous antheridia. 



The development of a very great number of antheridia 

 is an especial peculiarity which often occurs in the shoots 

 of the prothallia of ferns. They are either entirely barren, 

 or if antheridia are found, the latter are in great multitudes 

 and closely pressed together, there being often as many 

 as a hundred upon one shoot. I have never seen archegonia 

 upon one of these shoots ; they certainly have a tendency 

 to produce only male organs of fructification. 



Old abortive prothallia of Gymnogramma chrysophytta 

 often exhibit a very remarkable appearance in winter. 

 Near the hinder end several small oval knots of cellular tissue 

 are formed ; little knots varying from the size of a millet- 

 seed to that of a pea, and consisting of narrow cells filled 



