2SS 



On some remarkable Plants in the 



envelopes, in combination with the superior ovarium, and the 

 single ovulum. The chief characteristics of the whole group 

 (or class ?) appear to me to be the valvular perianthium, the 

 central free placenta bearing one or several ovula, the apices 

 of whose nuclei point to the fundus of the ovarium, and the 

 inverted embryo in the axis of copious albumen. This will 

 exclude Mackaya. Arnott, which nevertheless has strong 

 affinities with Santalaceae. * 



All these plants, so far as can be judged from the com- 

 parison of the direction of the apex of the nucleus, and that 

 of the radicle of the embryo, will probably be found to pre- 

 sent the same remarkable development of the seed, that has 

 been noticed in Santalum, Osyris, and Thesium. This appears 

 to be more worthy of notice, because in certain Verbenaceae, 

 in which the placenta and ovula are very like these bodies as 

 they exist in Olax, Schaepfia, Santalum, Osyris and Thesium, 

 the radicle of the embryo points, as it would be expected to 

 do, to the fundus of the fruit ; and in Avicenna means are 

 resorted to for preserving this normal direction, as extraordi« 

 nary as those occurring in the Santalaceae hitherto observed, 

 by which the inversion of the embryo is brought about. 



EXPLANATION OF PLATE XIL 



Jenkinsia Ass arnica. 



1. 



Portion of a male Plant. 



2. 2, 



Flower of ditto. 



S. 



Stamina of ditto. 



4. 



Female capitulum, in fruit. 



5. 



A fruit detached with its perianth and involucel. 



6. 



Section of fruit, so as to expose the pyrena. 



7. 



Seed, ventral face. 



8. 



Long section of seed. 



9. 



Transverse section of ditto. 



10. 



Embryo detached, one cotyledon removed. 



Figs. I, 2, 2, 3, from a drawing in H. C. Library. 



