Mr. J. Micrs on the genus Polydiclis. 361 



in the mouth, with five erect teeth, and enclosing' a nearly glo- 

 bular berry 4 lines in diameter. 



Polydiclis. 

 The Nicotiana quadrivalvis of Pursh, and the Nicotiana multi- 

 valvis of Prof. Lindley, have long been known as anomalous spe- 

 cies, which Don placed in his section Polydiclia of that genus, 

 and I propose to adopt that name, or rather its more correct de- 

 rivation, for a distinct genus, in order to embrace these plants, 

 which are distinguished from Nicotiana by the dififereut struc- 

 ture of the fruit and other characters. The first-mentioned plant 

 is a native of Missouri, where it is said to be cultivated as tobacco ; 

 it was introduced into England in 1811 and figured in the 

 ' Botanical Magazine.' The latter species was first cultivated in 

 England in 1826 and figured in the *^ Botanical Register/ They 

 both differ from Nicotiana in their globular, three or more celled 

 ovarium, with placentae projecting from the axis into the middle 

 of the cell, where they become thickened and ovuligerous. The 

 capsule is globular, often very large, umbilicate at the apex, three- 

 to eight-grooved, with as many corresponding septicidal valves, 

 which break away from the shriveled dissepiments. In Pohj- 

 diclis multivalvis, which has a six- or eight-celled ovarium, the pla- 

 centae are often pluripartite in each cell, and as they become in- 

 crassated, the fruit according to Dr. Lindley presents a series of 

 external spurious cells around the true seminal cavities. Its 

 generic name is derived from ttoXu?, multus, BikXU, valva, on 

 account of the greater number of the valves and divisions of its 

 capsule. 



Polydiclis (gen.nov.). — Calj/cc globoso-tubulosus, 10-16-nervis, 

 5-8-dentatus, dentibus valde acutis, insequalibus, erectis, per- 

 sistens et augescens. Corolla tubo cylindrico, 15- vel pluri-ner- 

 vio, basi ventricoso, calyce 2-3-plo longiore, limbo late campa- 

 nulato, ad medium 5-6-fido, lac'iniis expansis, obtusiusculis, 3- 

 nerviis, venisque anastomosantibus pictis. Stamina 5-6, in- 

 sequalia, inclusa, medio corollse inserta, filamenta tubo 3-plo 

 breviora, filiformia, anthera ovatre, 2-loba3, lobis liberis, appo- 

 sitis, rima exteriori dehiscentibus. Ovarium globosum, disco 

 carnoso insitum, 3 ad 6-loculare, placentis ex angulis promi- 

 nentibus in centro loculorum incrassatis, nmltiovulatis. Stylus 

 erectus, inclusus. Stigma clavatum, 3 ad 6-lobum, lobis ob- 

 tusis, expansis, glanduloso-papillosis. Capsula globosa, magna, 

 umbilicata, 3-12-sulcata, calyce aucto arete cincta, 3-pluri- 

 loculari, 3-plurivalvis, valvis septicidalibus dissepimentis de- 

 mum solutis, ssepe loccllis aliis spuriis exterioribus donata. 

 Semina plmuivd, parva, oblonga, compressiuscula, hilo laterah. 

 Embrf/o intra al/mmcn carnosum leviter incurvus, radicula te- 



