CONTRIBUTIONS TO BOTANY. 
225 
The Ehretia spinosa of Jacquin, judging from the characters 
he assigned to it, appears to differ in no way from Rhabdia, 
except in the pointed extremities of its deeply bipartite style : 
this plant constituted the second species of Don’s unrecognized 
and incongruous genus Lutrostylis, 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 Githa- 
rexylon barhinerve of Chamisso. 
It has already been mentioned that there exists in the or- 
ganization of the ovary and fmit 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 fm-nishes the nutrient ves- 
sels for the growth of the ovules ; the course of these vessels 
may always be traced through apertures existing in the nu- 
cules where they tenninate 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 Rhabdia, 
suprhj p. 219), 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 different genera of the Ehretiacece, and which 
serve at once to distinguish this family from the Cordiacece, 
Heliotropiacece, and Borraginacece. 
The following is a refomied diagnosis of the genus under 
consideration : — 
Ehretia, Linn. — Calyx parvus, persistens, subcampanulatus, 
imo crassiusculus, fere ad basin 5-partitus, laciniis subovatis 
aut subulatis, margine membranaceis et ciliatis, sestivatione 
imbricatis. Corolla gamopetala, hypogyna, membranacea, 
tubo saepius calycis longitudine aut paulo longiore, limbi 
lobis 5, oblongis, tubo paulo longioribus, revolutim expansis, 
asstivatione valde imbricatis. Stamina 5, altema ; filamenta 
compressa, subulato-filiformia, tubo affixa, exserta ; antheroe 
ovatae, 2-lobae, imo ad medium divaricatae, locellis sine con- 
nective adnatis, membranaceis, rima longitudinali lateraliter 
dehiscentibus. Ovarium conico-oblongum, disco parvo in- 
situm ; primum 1-loculare, semiseptis 2, parietalibus, oppo- 
sitis, in crura magna utrinque bilamellatim reflexis, ovulis 
accedentibus et deinde dissepimenta 2 parallela efformanti- 
bus, cum interspatio pro columella distincto ; columella cen- 
2g2 
