CAMPANULACEOTJS AND OLEACEOUS ORDERS. 13 



intermediate races which might have shown their special deri- 

 vation are lost to us. 



The Campanulese in which the capsular valves remain closed 

 and consolidated into a coriaceous or hardened, flat or convex, 

 apex, are numerous, and distributed into a number of more or less 

 distinct genera both in the northern and in the southern (South- 

 African) extratropical regions ; but the means of escape provided 

 for the seeds are quite different in the two regions. In the genera 

 jRoella, Prismatocarpus, TreicJielia, SipJiocodon, and Merciera, all 

 confined to South Africa, either the hardened apex comes off 

 bodily by a horizontal separation within or below the calyx-limb, 

 or the capsule opens below the calyx-limb in longitudinal fissures, 

 or (in Merciera) never opens at all. On the other hand, in the 

 great northern genera, chiefly Mediterranean, but some of them 

 extending all over Europe, central and northern Asia, and thence 

 to North America, Campanula, Specularia, Phyteuma, and the 

 more restricted AdenopJiora, Symphiandra, Michauxia, MusscTiia, 

 and TracTielium the dehiscence is peculiar. A small orbicular or 

 oblong portion of the pericarp below the calyx-limb and between 

 each two ribs separates in the form of a little valve, leaving a 

 pore or hole for the escape of the seeds ; or (in MusscTiia) a num- 

 ber of transverse slits are opened without any separable valve. 

 This mode of dehiscence, unknown in South Africa, must have 



had an exclusively northern origin and development ; whilst the 

 southern opercular or longitudinal dehiscences have never reached 

 Europe or extratropical Asia. 



SpTienoclea, a tropical weed common to both the New and the 

 Old World, is a very marked form of uncertain parentage. It 

 has, indeed, so little direct connexion with any one Campanula- 

 ceous genus that it has been raised by some to the rank of a di- 

 stinct order, although there is no character which it has not in 

 common with some portion of the tribe Campanuleaa. It is most 

 probably of African origin ; and the capsule has the opercular de- 

 hiscence of some of the South- African genera. 



The several species of Campanulese endemic in North America 

 are chiefly slight modifications of the widely spread northern Old- 

 World genus Campanula, or of its close ally or subordinate genus 

 Specularia. One species of the latter has spread far down the 

 Andine range of South America, where it has even formed some 

 slightly differentiated local races, varieties sometimes dignified 

 with the title of species. There is, however, one monotypic Cali- 





