M. Montagne 071 Me Podaxinese. Ill 



As this is the only species with which I am acquainted of a 

 green colour in its growing state, I was at first inclined to con- 

 sider it the Fragilaria confervoides of Greville ; but I have lately- 

 received from Mr. Harvey an authentic specimen of that plant, 

 which I have ascertained to be Fragilaria hyemalis, Lyngb. 



Ehrenberg describes his Frag, pectinalis as striated. I have 

 never succeeded in detecting the slightest appearance of striae on 

 the lateral sm'faces, although I have repeatedly and carefully ex- 

 amined them ', nor did Mr. Berkeley, to whom I sent specimens, 

 perceive them. On the other hand, Mr. Dalrymple observes, 

 that the striae, though difficult to see, are nevertheless present. 

 Mr. Jenner, who is a very accurate observer, thinks that there 

 are very faint, almost obsolete strise, which can be only seen when 

 the endochrome is removed : in another letter, however, he enu- 

 merates the absence of strise among the characters of the species. 

 Thus it will be seen, that even if strise are present in this plant, 

 they cannot be adopted as one of its characters without the risk 

 of misleading the observer. 



Plate II. fig. 6. a, states of i^. virescens; b, fmstules, deprived of their 

 endochrome ; c, lateral view. 



Analysis. 

 "The margins of the lateral surfaces flat or concave on 



one side, and on the other convex pectinalis. 



The margins of the lateral surfaces convex and similar 

 on both sides 2 



rt / Lateral margins with distinct evident puncta hyemalis. 



'\ Lateral margins without puncta 3 



r Frustules very narrow, the puncta at their ends indi- 



ft J stinct or wanting rhahdosoma. 



'I Frustules rather broad, with two evident puncta at each 

 I end virescens. 



[To be continued.] 



XVI. — Considerations on the tribe of the Podaxinese, and descrip- 

 tion of the new genus Gyrophragmium. By M. Montagne*. 



Amongst the Trichogastrous Fungi there is a small tribe which 

 has recently been raised to the rank of a family by M. Corda, and 

 which is remarkable among other characters by the presence of a 

 columella traversing the axis of the peridium : it is the Podaxinea. 

 This tribe, which was formerly composed of the three genera Cy- 

 cloderma, Klotzsch, Cavloglossum, Greville, and Podaxon, Desvaux, 

 became all at once doubled by the addition of three others, the 

 Secotium, Kunze, the Polyplocium, Berkeley, and the Gyrophrag- 

 miunij nob., which forms the principal object of this notice. 



* From an extract by the Author in the * Comptes Rendus,' No. 16, 1843. 



1. 



