594 GENTIANALES. [Perigynous Exogens. 



Alliance XLV. GENTIANALES.— Tre Gentianal Alliance. 



Diagnosis. — Perigynous Exogens, with dichlamydeous monopetalom flowers, axile or 

 parietal placentae f and a minute emlryo, or tvith the cotyledwis much smaller than the 

 radicle, lying in a large quantity of albitmen. 



Here we find ourselves among the truly monopetalous Orders of the French school. 

 Previously a monopetalous structvu'e was an exception rather than a rule ; but now a 

 separation of petals forms the exception. Tendencies have assumed a new du-ection. 



The Alliance differs from that of Solanals in having a minute embryo and much albu- 

 men, and from Cortusals in the placenta never being free and central. It touches So- 

 lanals at Nightshades themselves, which, if they had parietal placentse might often be 

 mistaken for Gentianworts ; and at Dogbanes, whose minute embryo offers one of the 

 principal reasons for not associating them in the same AlHance as Asclepiads. With 

 Cortusals Gentianals come in contact through Ebenads, which are very like Ardisiads, 

 and Diapensiads, which may be compared to Primworts. To Bignonials they are very 

 closely alHed through Broomrapes and Stilbids, which put on the peculiar aspect of that 

 AUiance. 



Natural Orders of Gentianals. 



Stipules 0. Stigmas simple, sessile, radiating 229. Ebenace^. 



Stipules 0, Stigmas simple, at the end of a manifest style. Pla- 1 90 a a 



centcB axile. Seeds definite, pendulous. Corolla imbricated . J '^'^^- ^Quifoliace^. 

 Stipides 0. Stigmas collected into a massive head, expanded at "I 



the base in the form of a nng or membrane, and contracted in 1 231. Apocynace^. 



the middle. (Albumen sometimes d) J 



Leaves opposite, with intervening stiptdes 232. Loganiace^e. 



Stipules 0. Stigmas simple, at the end of a manifest style. Pla- \(^oo T^ 



centce axile. Seeds indefinite, peltate. Stamens interpetalous . J i^iapenstace^. 



Stipules 0. Stigmas simple, at the end of a manifest style. Pla-^ 



centcB aocile. Seeds definite, erect. Corolla valvate. Flowers 1 234. Stilbace^. 



unsymmetrical J 



Stipules 0. Stigmas simple, at the end of a manifest style. Pla- \co^ ^ 



centce parietal. Floivers didynamous j "^^- '^ROBanchace^, 



Stipules 0. Stigmas simple, at the end of a manifest style. Pla- 1 00^ r< 

 centce parietal. Flowers regular ......... . 1 236. Gentianace^. 



