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Descriptions of ColumeUia, Tovaria, and Fraiicoa ; with Re- 

 marks an their Affinities. By Mr David Don, Librarian 

 of the Linnean Society, Member of the Imperial Academy 

 Naturae Curiosorum, of the Royal Botanical Society of Ra- 

 tisbon, and of the Wernerian Society of Edinburgh, &c. 

 Communicated by the Author. 



A HESE genera were estabhshed many years ago, but, from 

 the imperfect nature of the descriptions published of them, their 

 affinities have remained hitherto undiscovered, and the real na- 

 ture and structure of several of their parts of fructification have 

 been either wholly overlooked, or but partially understood. The 

 object of this communication, therefore, is to give complete de- 

 scriptions, and to point out the distinguishing characteristics of 

 these genera, with a view to determining the stations they seve- 

 rally occupy in the Natural System. In the accomplishment 

 of this object, the extensive collections of the authors of the 

 Flora Peruviana, now composing part of the Lambertian Her- 

 barium, have been of essential service, as they contain numerous 

 specimens of ColumeUia and Tovaria, two genera first proposed 

 in the above-mentioned work. 



It is a just observation, that the ascertaining the true charac- 

 ters and affinities of genera already established, is much more 

 important to the advancement of science, than the addition of 

 new ones, at least where these do not develope any very import- 

 ant modifications of structure. The genus first in order is Colu- 

 meUia, of which I shall now proceed to give a detailed descrip- 

 tion. 



Syst, Linn. DIANDRIA MONOGYNIA. 

 Ord. Nat. COLUMELLIE^E, nobis. 



COLUMELLIA, Ruiz Ct PavOU ^llLtJltlA, JUSS. 



Calyx monophyllus, turbinato-tubulalus, adnatus, leviter ancipiti-compressus i 

 limbo persistente, 5-lobo : laciniis subaequalibus. Corolla summo tubo caly- 

 ds inserta, rotata, limbo 5-loba, concava : lobis aequalibus, rotundatis, in- 

 tegerrimis, aestivatione convoluto-imbricatis, calycinis laciniis alternanti- 

 bus. Stamina 2, corollae fauci incrassatae inserta, angulis calycis opposita : 

 fiiamenta brevissima, dilatata, complanata : antherce triplici modo bicrures, 

 replicatae ! (hinc trilobatae depictae in Fl. Peruv. Gen. t. 1.) loculus unicus 

 tantum, per omnes convolutiones continuatus ! angustissimus, cartilagi- 

 neus, fissura longitudinali dehiscens. Pollen angulatum, resinosum. Ova- 



