178 



2. MONOPETALOUS PLANTS. 



The character by which this division of Dicotyledons is distinguished from 

 the last (p. '2.), is the cohesion of the edges of the petals into a tube; 

 whence the name Monopetalous, the petals forming together a single floral 

 envelope. Generally it is easy to recognise this character, and the orders 

 thus, distinguished are individually perfectly natural ; but occasionally cer- 

 tain genera in Polypetalous orders have flowers with a Monopetalous corolla, 

 as in Crassulacese ; these cases are, however, rare, and are to be considereti 

 exceptions to the rule. For the most part, in Monopetalous plants belong- 

 ing to Polypetalous orders, the petals are readily separable from each* other, 

 which is not the case in genuine Monopetala' ; but this is not always so. 

 Apetalous exceptions are exceedingly uncommon : Glaux, among Primulacese, 

 is a rare instance of this. 



Monopetalous orders approach those which are Polypetalous, Apetalous, 

 or Achlamydeous, at many points besides such as are adverted to at p. 2, 

 especially by Ilicineae, which are nearly allied to Rhamneae. 



LIST OF THE ORDERS. 



166. 

 167. 

 168. 

 169. 

 170. 

 171. 

 172. 

 173. 

 174. 

 175. 

 176. 

 17*7. 

 178. 

 179. 

 180. 

 181. 

 182. 

 183. 

 184. 

 185. 

 186. 



Ificineae. ' 



Styraceae. 



Belvisiaces. 



Sapoteet. 



Ericese". 



Epacridese. 



Vacciniete. 



PyrolaceaL'. 



Campanulacese. 



Lobeliaceae. 



Gjoodenoviae. 



Stylideae. 



Scauvoleae. 



Bniuoniacese. 



Papayacece. 



Cucurhilaceic. 



Plaiitaj^inea;. 



Pluml)agiiiea2. 



Dipsacou'. 



Valerianea;. 



Composita;. 



CLXVI. 



Ilicine.t,, Ad. Brominiart Memoire sur les Iihamn(es, p. 16. (182f!) ; JJndL Spwps. p. TX 



(li!2!») AuiiiFOi.iACE.i',, Dec.Thiorie, ed. 1. 217- (1813); a sect, o/ Celastrineae, 



lb. Prodr. 2. 11. (1825) ; Martius II. R. Mon. (1«2!).) 



Diagnosis. Monopetalous dicotyledons, with a superior 2-6-cclled 

 ovarium, regular flowers, definite pendulous ovules, a 4-6-lobed corolla, 

 with the stamens equal to the number of its lobes, and albuminous seeds. 



