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X. Additional Observations on the Tropaeolum pentaphyllutn of Lamarck. 

 By Mr. David Don, Lihr. L.S. 



Read March 18th, 1834. 



In the account of this remarkable plant already given, at page 11,1 omitted 

 to notice several interesting facts, which an examination of living specimens in 

 "a more perfect state has enabled me to supply, and which greatly strengthen 

 its claims to be regarded as the type of a distinct genus. The first character 

 I shall have to notice is the persistent nature of the calyx, so different from 

 that of Tropceolum, which is strictly deciduous. Not only is the calyx per- 

 sistent, but it undergoes considerable changes during the progress of the fruit 

 towards maturity, at which period it will be found to have increased very 

 much both in size and thickness, its vitality continuing undiminished until 

 the decay of the stem that supports it. In the advanced state, the tube or 

 spur assumes a fleshy consistence, and is abundantly supplied with a honey- 

 like fluid, its extremity being partially separated from the rest by a constric- 

 tion, as if foruied by a ligature, and finally withering and falling ofij while the 

 other parts remain in a healthy state. 



The internal structure of the seeds differs materially from that of Tropaeo- 

 lum; the embryo is small and white, contained in a thin cartilaginous testa; 

 and the cotyledons round and compressed. 



I would therefore propose the following additions to the technical part of 

 my former description. 



Calyx persistens, demilm, fructu maturescenti, vald^ auctus, carnosus : cal- 

 cari infundibuliformi, infernfe constricto, extremitate clavata mellifera 

 decidua ! Seminis testd cartilaginea, alba. Embryo parvus, albus : cofy- 

 ledones subrotundse, compressse. 



VOL. XVII. tJ 



