adverting to the late Mr, Griffith, 377 



ing up of the tissue, terminating and closing what he calls the style, 

 that is to say, the point of the pistillidium, subsequently to the ap- 

 plication of a particular matter, whereby the style becomes a canal, 

 opening externally by a browning observable in the orifice of this 

 canal extending downwards until it reaches the cavity of the (his) 

 ovary, and by a corresponding enlargement of a cell (his ovule) 

 existing in that cavity. Mr. Valentine, however, does not regard 

 these appearances as connected with fecundation. 



MARSILEACE.E. 



72. Following Jussien, Salvinia and Azolla were separated in the 

 last edition of this work as a distinct natural order, a view that 

 Endlicher has since taken. But upon a full consideration of the 

 structure of these plants, or of what is known of it, it does not ap- 

 pear to justify the separation. Like Pilularia and Marsilea, they 

 have two distinct kinds of reproductive bodies enclosed in involucres, 

 and that seems to be the main feature by which Pepperworts are 

 known as an order from Lycopodiaceoe. For the same reason it ap- 

 pears better to combine with them Isoetes, instead of regarding that 

 too as the type of still another order. Mr. Griffith does not include 

 Isoetes among these plants ; but I cannot assent to the propriety of 

 erecting every genus in this curious order into a suborder. 



The genera Salvinia and Azolla have been the subject of some 

 elaborate observations by Mr. Griffith, (Calcutta Journal, Vol. V.), 

 who elevates each into a suborder, and throws an entirely new light 

 upon their structure. He regards them as having true sexes, the 

 male being certain necklace-shaped threads found, at an early stage, 

 in contact with what he denominates an orthotropous ovulum. But 

 strange to say, this so called ovulum, instead of giving birth to an 

 embryo, becomes the parent of reproductive bodies of two totally 

 different kinds, having not even the smallest resemblance the one 

 to the other, although the matrix out of which they are evolved 

 is identical at an early period of the organization. I regret that 

 Mr. Griffith's most curious memoir only reached me as this sheet 

 was going to press, so that it was impossible to have cuts prepared 

 to illustrate his observations, for which the reader is referred to the 



