298 Mr. E. Kidston on the Affinities of the 



The genus was founded by Dr. Paterson * for the reception 

 of a curious fossil collected by him " in a mass of bituminous 



shale from the coal strata which are exposed along the coast at 



Granton, and nearly opposite Professor Hope's residence." 

 In discussing the probable affinities of his plant he saysf : 

 " In taking a general view of this fossil, there are several living 

 genera of plants to which it bears a resemblance, as Typha, 

 Calamus j Peperomia, and Pothos. It will not be necessary to 

 describe minutely the resemblance which it bears to either the 

 Calamus or Peperomia, as it is distant, and does not stand 

 minute examination. The first and last of these therefore, 

 viz. the Typha and Pothos, it will only be necessary to enter into 

 minute comparison with it. 



u It approaches the genus Typha in having the reed-like 

 stems, which terminate in a cylindrical head, and that head 

 having one and occasionally two divisions. Although, 

 however, this general description agrees, on more minute 

 examination it will be obvious that it cannot be referred to 

 the genus Typha. The pericarp in the genus Typha is sur- 

 mounted with a feathery pappus, and has no scales surrounding 

 the germen. Our fossil may have been a monoecious plant 

 (the upper male part being wanting) ; but at all events it 

 must have been a tetrandrous plant, from the remains of the 

 four projections, which are represented in the magnified 

 drawing. There is no appearance of there having been any 

 pappus whatever, and therefore it is more likely to be referred 

 to the genus Pothos. This class of plants, viz. the genus 

 Pothos, is characterized by its spatha being monophyllous 

 spadix cylindrical, thickly set with flowers, perianth tetra- 

 phyllous, berry or capsule tetraspermous, the latter of which 

 is occasionally terminated by four obtuse angles. They 

 belong to the natural order Aroidece. The characters of this 

 class of plants will be found to apply very nearly to our 

 present fossil, making allowance, of course, for the compression 

 it has undergone, and the change of appearance produced by 

 its mineralization. 



" The greatest number of the species of the genus Pothos 

 are parasitic, and inhabit the vast forests of tropical countries. 

 In some of the species, also, there are truncated fleshy scales 

 on each side of the germen, and which, in the young state, 



? 



completely cover the male organs of the plant; these are 

 especially conspicuous in P. acaulis. The similarity of the 



* Paterson, 



table from 

 pi. iii. 1841. 



t Paterson, " Description oi Pothocites, &a," /. c. p. SO. 



m, "Description of Pothocites Grantonii, anew Fossil Vege- 

 the Coal Formation;' Trans. Dot. Soc. Edinb. vol. i. p. 45, 



