Mr. J. Miers on the Elirctiacea?. 107 



merated by DeCandolle enter into the genera Bourreria and 

 Crematomin : these are distinguishable at a glance from Ehrefia 

 by their much larger, tubular, fleshy calyx, terminated by five 

 teeth with thick tomentous margins, which are valvately closed 

 in ajstivation, and afterwards sometimes adhere so strongly 

 together as to be separable with difficulty. 



The Ehretla sjyinosa of Jacqnin, judging from the characters 

 lie assigned to it, appears to ditfer in no way from Rhabclia, 

 except in the pointed extremities of its deeply bipartite style : 

 this plant constituted the second species of Don's unrecognized 

 and incongruous genus L^itrosti/lis, the type of which, the 

 Ehretia fasciculata of Kunth, is of very different structure, 

 and will presently be noticed; his third species was the Ehretia 

 montevidensis of Sprengel, which, from Sellow's original spe- 

 cimen in the Berlin Herbarium, has proved to be the Citha- 

 rexylon harhinerve of Chamisso. 



It has already been mentioned that there exists in the or- 

 ganization of the ovary and fruit of the Ehretiacece a point 

 of structure which has escaped general observation : this 

 is, the placentation of the ovary, and the existence of a 

 gynobasic or central column which furnishes the nutrient ves- 

 sels for the growth of the ovules ; the course of these vessels 

 may always be traced through apertiu-es existing in the nu- 

 cules where they terminate in the funicular points of suspen- 

 sion of the seeds. Hence the frequent geminate connexion of 

 the distinct nucules in pairs in this family, a connexion effected 

 either through a chink on one side only of each cell, some- 

 times near the summit (as I have already shown in Bhahdia, 

 ante J vol. ii. p. 432), or sometimes, through the intermedium of 

 a pseudo-cell, from a large opening above the base, as is seen 

 in Bourreria : these modifications furnish good characters, 

 which mark the difierent genera of the Ehretiacece^ and which 

 serve at once to distinguish this family from the Cordiacece^ 

 Heliotropiaceai^ and Borraginacece. 



The following is a reformed diagnosis of the genus under 

 consideration : — 



Ehretia, Linn. — Calyx parvus, persistcns, subcampanulatus, 

 imo crassiusculus, fere ad basin o-partitus, laciniis subovatis 

 aut subulatis, margine membranaceis et ciliatis, jestivatione 

 imbricatis. Corolla gamopctala, hypogyna, membranacea, 

 tubo SEepius calycis longitudine aut paulo longiore, limbi 

 lobis 5, oblongis, tubo paulo longioribus, revolutim cxpansis, 

 festivatione valde imbricatis. Stamina 5, alterna; jilamenta 

 compressa, subulato-filiformia, tubo affixa, exserta ; antheroi 

 ovatas, 2-loba?, imo ad medium divaricata^, locellis sine con- 



