161 



Original %ttit\c0. 



ON DEIDAMIA THOMPSOiS'IANA, DC. 



By Maxwell T. Masters, M.D., F.E.S. 



(Tab. 163.) 



My attention has been called to this plant by the Editor of this 

 Journal, who has kindly allowed me the opportunity of examining 

 the specimen in the Herbarium of the British Museum, to which is 

 affixed a label in Brown's handwriting with the inscription, " Thomp- 

 sonia, Madagascar, Thompson." 



The plant is interesting, both structurally and geographically. It 

 furnishes a link between the true Passion-flowers and the Modeccas, and 

 it is the type of Brown's genus Thompsonia, the validity of which, as 

 distinct from Deidamia, Thouars, has been doubted. Some account of 

 the plant may therefore be of interest, the more so as Brown said very 

 little concerning it, and Tulasne, who monographed the genus Dei- 

 damia, had no specimens before him of this particular species. 



Before describing the plant and discussing the points of interest 

 that arise from its examination, it will be well to give a brief summary 

 of its history so far as it is known. 



The first reference is that of Robert Brown, in his famous Rafflesia 

 paper, ^' where, in alluding to the indefinite number of stamens in 

 Smeathmannia, he says, '^an approach to this structure is already 

 known to exist in an unpublished genus {Thompsonia), discovered in 

 Madagascar by Mr. Thompson, of which the habit is entirely that of 

 Deidamia^ and whose stamina' are equal in number to the divisions of 

 both series of theperianthium," I have not been able to find any other 

 reference to this Thompsonia in Brown's writings. 



Auguste Pyrame DeCandolle was the next to advert to the plant, 

 •and he, in the third volume of the Prodromus (1828), p. 337, referred 

 it to Deidamia Thompsoniana, having apparently examined a specimen 

 in Lambert's herbarium, where it was labelled by Thompson as Passi- 

 flora octandra. Endlicher, in his Genera, p. 925, n. 5096 (1836-40), 

 describes the genus Thompsonia apparently from actual specimens, 

 seeing that he describes the conformationof the flower much more fully 

 than his predecessors had done. 



Roemer, in his Synopsis Monogr., fasc. ii., p. 138, refers to the plant 

 as Thompsonia Brownianay but he probably had no personal know- 

 ledge of it. 



Tulasne, in the Ann. So. Nat. Bot. (1857), p. 51, describes the 



* Trans, Linn. Soc. xiii., 220, adnot. (read June 30, 1820), Miicell. Botanical 

 Works ed. Bennett, i., p 387, adnot. 



N.s. VOL. 4. [JuxE, 1875.] II 



