I860.] FLEMING SOCIETY OF NATUllAL SCIENCE. 61 



FLEMING SOCIETY OE NATUEAL SCIENCE. 



SESSION IX., MEETING III. 



The Society met in the New College, on Tuesday, 10th of 

 January, at eight o'clock. John A. Stewart, Esq., in the Chair. 

 The following papers were read : — 



I. Ferns; their structure, propagation, development, culture, 

 geographical distribution, uses, classification, and diseases : by 

 Mr. W. Ramsay M'Nab, Librarian and Curator of Museum, — 

 Mr. M'Nab, in his paper, which was a most elaborate one, 

 touched at greater or less length on the various points enume- 

 rated in the title. While examining the difference between a 

 seed and a spore, the author remarked, that in the seed the root 

 came from a fixed point, but in the spore it did not. He took 

 as an example of an ovule the ovule of Nymphcea alba. When 

 the seed was sown, the root was produced from the same point in 

 all the seeds of the NymphcBa ; and that at a diametrically oppo- 

 site point the stem or ascending axis was developed. This law he 

 proposed to call the "Law of adverse directions" — a law which is 

 never violated. He promulgated another law, — which is present 

 only in Phanerogamece, — that "The radicle is always produced 

 from one fixed spot," viz. the micropyle. The author observed 

 that although the spores of the Cryptogamecs were homogeneous 

 in their structure, and the radicle descended from any point of 

 the surface, the stem was always produced at the diametrically 

 opposite point ; while in the seed of Phanerogamece the root came 

 from a fixed point. The part of the spore which was downward 

 produced the root, and that which was upwards the stem. The 

 foregoing points constituted the greatest difiference between the 

 seed of a flowering and a flowerless plant, — the latter of which 

 he proposed to call the " Law of spontaneous ascendance and 

 descendance." The classification which Mr. M'Nab adopted 

 was very little different from that of Mr. Babington (Man. of 

 Bot.), but he had been principally engaged in examining the 

 different tribes and genera. The principal difference was that 

 he had divided some of the genera into subgenera, as for ex- 

 ample : — In Tribe L, Polypodies of Bab., there were the follow- 

 ing genera and subgenera: — 1. Allosorus ; 2. Polypodium, which 

 he had divided into two, viz. a. Polypodium verum, fi. Pseudo- 



