388 Mr. J. Mievs on the Ehretiaceae and Cordiaceae. 



three abortive cells ; the seed is here fixed above the middle 

 of the cell, with a conspicuous descending raphe terminating 

 in the basal chalaza. Myxa will make a good genus com- 

 posed of several species, only a comparatively small portion 

 of the 122 species classed in the section Myxa by De Candolle. 



Cordia might conveniently be divided into several genera, 

 for which good differential characters now exist. The form and 

 aestivation of the calyx have already served for sectional divi- 

 sions ; but those of the corolla have been little attended to. 

 Prof. De Candolle has noticed that the border of the corolla \ i 

 campanulate and plicated convolutely in Varrotiia, as in the 

 Convolvulacexv • in C. decandra, Hook. & Arm, and C. angio- 

 carpa, Rich., the stamens are twice or three times the usual 

 number, and the lobes of the corolla, which are equally nu- 

 merous, have a contorsively imbricated aestivation : in some 

 species the border is corrugated, but in general the lobes 

 of the border are quincuncially imbricated, in aestivation. It 

 has not been noticed that in all the species forming the section 

 Gerascanthus the border is cleft to the base into five equal 

 flat lobes, which in aestivation are folded sinistrorsely, as in 

 Echites : this generic name, established by P. Brown, might 

 therefore be restored. The section Rhabdocalyx has one lobe 

 of the border external in aestivation, while the other four are 

 convoluted. The characters of the stamens and fruit afford 

 other good indications. Besides the features I have men- 

 tioned as distinguishing Myxa, may be added that of its 

 polygamous or monoecious flowers. Cordia, indeed, stands 

 in much need of a thorough careful examination and redistri- 

 bution. 



There is one point deserving of notice — that, from some un- 

 known cause, it rarely happens in Cordia that more than one 

 ovule becomes fertilized; and this occurs equally in the plants of 

 the Old and New World. The drupaceous nut is usually more 

 or less gibbous and one-celled, with the seed attached as above 

 described, in which case the abortive cells are generally seen 

 on the flattened side, above the middle. May this almost 

 constant abortion be owing to a defect in the stigmata, or to 

 the puncture of insects, attracted perhaps by the nectariferous 

 gland ? I have seen cases where the flowers on a branch ap- 

 peared quite perfect, but there was hardly one ovary in the 

 whole that had not been attacked by a minute grub. 



On a future occasion I will call attention to a new group of 

 plants (the Auxemmaceai) , closely allied to Cordiaceos, distin- 

 guished by the great augmentation of the calyx in fruit, by 

 the peculiar aestivation of the corolla, and by its atropous 

 ovules and seeds. 



