4,12 NATUliAL IflSTnRY OF PLANTS. 



insertion, like tlie P;conies ; that Crossosomn, whether we make it 

 belong' to Ranuncuhiaue, or its next-door neighbour Dilleniacea, has an 

 uninistakoably concave receptacle, and that in this same order DWeni- 

 nceie, there is one llibberfia with the receptacle of Potentilla, though 

 it is quite insej)arable from the other Hibhertias, and at one time 

 placed among Rosacea under the name of Warhurtonia. 



There arc two other orders, so closely allied with Rosacea, so 

 little distinguished by any absolute character whatever, that their 

 separation from it must be regarded as a matter of pure convention, 

 these arc Saxifragacece and Lefjuminosa. 



As regards the former we do not refer to the commonest type, repre- 

 sented by the Saxifrages themselves and the allied herbaceous genera ; 

 the knowledge of these types, more widely diffused than that of the 

 |)eripheral genera of the natural order, has led most authors to leave 

 SiLvifragacecB among the group of orders with parietal placentation, 

 and there we too shall leave them ; for in a linear series it is impos- 

 sible to consider simultaneously all affinities and characters of im- 

 j)ortanco. But apart from the fact that most natural orders whose 

 flowers have gyna3ceums with several free carpels, may also include 

 genera, which though otherwise quite similar, have their carpels 

 united edge to edge into a single ovary with several parietal pla- 

 centas :' we have in the tribe Cunoniece genera whose carpels are 

 free, or nearly free, and flowers altogether formed like those of 

 several Spireece ; the fruit, inflorescence and habit, are the same on 

 both sides, so that it will thus be understood how certain genera 

 have been placed under different names in SaxifragacecB and Rosacea 

 indilVcrently." True, there is one way, regarded as entirely infal- 

 lible till quite recently, to distinguish the two orders, when we can 

 examine the structure of the seeds ; those of the former order having 

 been considered as invariably albuminous, of the latter invariably exal- 

 buminous. But now unfortunately this is lost as a distinctive cha- 

 racter, for we know many Rosacea whose embryo is surrounded by a 

 more or less abundant layer of perisperm, as we have seen in the 



' Such B8 Monodora in Anonacea, Berber/- Rosacea;, under the respective names of Adeni- 



(lopti* in BrrUridficpfr, CaneUcie in Magna- lema and Hoteia. Luetkea or Eriogyna, whicn 



/i<io.r. Ax-. (Seepp. 119, 15'j, 160, 239, 255). is really only a member of Spireeee had also 



' We need only recall the fact that Neillia been considered a genus of the order Saxi- 



1ns l)cen classed among Saxifrar/aceee, and As- fra/jaceiB. 

 tube was for some time regarded as belonging to 



