250 Mr. J. Miers on the genus Dyssochroma. 



Dyssochroma. 



A recent inquiry into the different species of SolandrUj with 

 the view of determining the true Umits of that genus, has con- 

 vinced me that a considerable difference of structure exists be- 

 tween Solandra grandiflora and S. viridijlora ; upon comparing 

 these carefully, we cannot fail to arrive at the conviction, that 

 these two species must be held to be generically distinct. In 

 the former instance, the calyx has the shape of a large and cylin- 

 drical tube, irregularly cleft in the mouth into three unequal 

 rather short teeth; it does not increase in size, but, in consequence 

 of the growth of the fruit, splits on one side, by a longitudinal 

 fissure, to the base ; in S. viridijlora, on the contrary, the calyx 

 consists of five, very distinct, lanceolate divisions, all free to the 

 base, which at first are slightly connivent by their somewhat 

 thickened margins, but which are easily, and soon become, sepa- 

 rated into distinct sepals. The corolla in Solandra grandiflora is 

 much larger, more campanulate, of thicker consistence, of a yel- 

 lowish colour, with deep red nervures, and with a border of five 

 large rounded lobes, remarkably crenated or fimbriated on their 

 margin, and these are considerably imbricated in aestivation, one 

 lobe being quite interior, and another altogether exterior : the 

 stamens are also very glabrous. On the contrary, in S. viridiflora, 

 the corolla, of a greenish lurid white, is deeply divided (half-way 

 down) into five equal, revolute, lanceolate, acuminated and entire 

 segments, which are quite valvate in sestivation, and connivent 

 by their somewhat inflected tomentose margins : the stamens are 

 swollen and very sericeously pilose at their base ; in drying, both 

 calyx and corolla become black, which does not occur in the true 

 species of Solandra : in the latter genus the flowers are always 

 terminal, whereas in S. viridiflora they are solitary and axillary, 

 or at least grow out of several nearly terminal axillary fascicles 

 of leaves : there are some other minor points of difference that 

 will be traced in the details of the characters described. From 

 these facts it will be seen that the new genus, of which the ^o- 

 landra viridiflora may be considered the type, must be referred 

 to the true Solanacece, and that it will belong to the Jaborosece, 

 serving to connect that tribe with the lochromea, and closely 

 allied to Salpichroma and Nectouxia. I have called it Dysso- 

 chroma, from ^■uaaoo<;, ceger, and '^^pwjjba, color, on account of the 

 lurid sickly green colour of its large flowers, which become black 

 as they wither, or lose their moistm'e in drying, a character com- 

 mon to all the Jaboroseae. I have not been able to examine the 

 embryo of this genus, but we may expect it will prove very differ- 

 ent in form from that of Solandra. The following may be consi- 

 dered as its generic character : — 



Dyssochroma, gen. nov. — Calyx magnus, 5-sepalus, persistens ; 



