MR, G. BENTHAM ON EUPHORBIAOEJi. 205 



3. Btjxe^:. 



Buxus bad always been regarded, as it still is by most bota- 

 nists, as a genus of biovulate Euphorbiaeese, until Baillon ob- 

 served that the position of the ovules was somewhat different 

 from that in the other genera. The two ovules of each cell are 

 separately affixed to the dissepiments, one on each side of, and 

 at some distance from, the central angle, with the raphe more or 

 less dorsal, and the micropyle turned towards the dissepiment or 

 towards the central axis ; whilst in the generality of Euphorbiaceae 

 the two ovules are affixed close together in the angle of the cell, 

 and often under one common obturator, and the micropyle is 

 external. He therefore proposed raising the genus to the rank 

 of a distinct order, adding to it the closely allied genera Pachys- 

 andra and Sarcococca ; and in a detailed monograph of the new 

 order he summed up (p. 5) the several characters of Buxus, 

 "qui ne se rapportent aucunement aux plantes de l'Ordre des 

 Euphorbiacees," under the following seven heads : 



1. Opposite leaves — which are not in Pachysandra or Sarco- 

 cocca, and are now known as characteristic of at least a dozen 

 genera of true Euphorbiacese. 



2. Absence of milky juice. This milky juice, though generally 

 prevalent, is far from being universal in Euphorbiaceae. 



3. Styles distant from each other at the base, leaving the 

 summit of the ovary bare between them. In Buxus subcolum- 

 naris, and most if not all species of Sarcococca, however, the styles 

 are not only close together, but shortly united at the base, 



4 and 5. The above-mentioned position of the ovules — which 

 appears to be the only constant character of the group. 



6. The micropylar strophiole replaced by a fleshy production 

 of the hilum. Baillon himself has described a similar produc- 

 tion in some other genera ; and in many cases the origin of the 

 appendage at or near the insertion of the seed has not yet been 

 satisfactorily traced. 



7. The loculicidal dehiscence of the capsule. But Sarcococca^ 

 and apparently one species of Pachysandra, have an indehiscent 

 drupe ; and loculicidally dehiscent capsules occur in several tribes 

 or subtribes of Euphorbiaceae. 



To the above three genera Baillon added Kunth's Styloceras, 

 as a separate division of the proposed order, differing from the 

 typical one in the number, form, and insertion of the stamens, 



LINN. JOURN. — BOTANV, VOL. XVII. R 



