14 



are certain ; besides these there are 29 which the author 

 has not seen, and which are doubtless in some cases synonyms 

 of others. 



A work more grateful than this to systematic botanists 

 could hardly have been undertaken ; for if there was one 

 genus more difficult than another among Ferns it was cer- 

 tainly Pteris. The author's great object has been to elucidate 

 the synonymy, and he appears to have done so with much 

 skill and success, as may be seen from the result of his en- 

 quiries into a few cases. P. angusta, elastica, and masca- 

 renensis are the same as P. scahra; P. arguta, palustris, and 

 lata belong to P. flahellata ; and, finally, P. discolor, glau- 

 cescens, cruciata, sinuata, Lessoniana, and vespertilionis, and 

 perhaps P. pallida, are referred to P. elegans. So that no 

 fewer than sixteen are reduced to three. It is probable that 

 few large genera exist, upon which numerous botanists have 

 worked independently, in which similar reductions of species 

 might not safely be made ; and if so, what opinion is the 

 statistical enquirer to form of the actual number of Vegetable 

 species known to science ? 



FRUIT OF LEPTOTES BICOLOR, AROMATIC. 

 Professor Morren has ascertained that the fruit of this 

 pretty epiphyte, figured in the present work, vol. 19, t. 1625, 

 is fragrant when ripe. By fertilizing it artificially, he suc- 

 ceeded in twice obtaining its fruit, which he describes as re- 

 sembling in smell the well-known Tonka or Tonquin bean of 

 the perfumers ; or the Sweet-vernal Grass (Anthoxanthum 

 odoratum), which aromatises hay, only stronger and more 

 penetrating than the last. It has been found that this fruit, 

 infused in cream or milk, gives them, when iced, a mild 

 agreeable flavour, sweeter than Vanilla but less penetrating. 

 *' L'homme," adds the author, " est avide de varietes dans sa 

 nourriture; Fart culinaire trouve i9i un moyen de plus de 

 contenter ses gouts capricieux, et I'art du glacier de diminuer, 

 chez ses produits, cet ennui qui, dit-on, naquit de I'uni- 

 formite." 



ON THE MOTION OF GUM IN PLANTS. 

 In his investigation of the anatomy of Cycadacese, Pro- 

 fessor Morren has arrived at a fact of great interest in Vege- 

 table physiology. It is well known that all these plants yield 



