It f the Exlenial Coatings of Srrds. 279 



an expansion ot" the placcntary sheath, 1 have called an ari/line*, 

 to distinguish it from the true orillus, which is always more ex- 

 terior to it, and not necessarily fleshy, and which is an emana- 

 tion from, or j^rowth of, the funiele. If the term ariUine, which 

 is identical with the arillode of Planchon ayd the faux arille of 

 St. Hilairc, he objected to, it is easy to give it another namej 

 but that coating, in no case, can be considered to be the testa, 

 though sometimes confluent with it. 



These considerations are perfectly consistent with the doc- 

 trines of Brown and Mirbel, now universally adopted by botanists, 

 in regard to the development of the coats and nucleus of the 

 ovule and the mode of its fertilization and growth. 



The question in regard to the seed-coats of Magnolia having 

 been fully discussed in ray former pa])er f^ I need only here refer 

 to the main points at issue in that case. Dr. Asa Gray, having 

 at first overlooked the existence of the inner integument, was 

 led to conclude that the two outer tunics of its seed are the 

 growth of the two coats of the ovule J; but he afterwards ad- 

 mitted that its bony shell must be held to be its testa § ; at the 

 same time, not prepared to renounce his favourite prepossession 

 that the scarlet coating is a growth of the primine, he main- 

 tained that the two constituted one integral tunic, " a baccate 

 testa :" this term, of no definite meaning, was invented by Lin- 

 n?eus, prior to the existence of any distinct nomenclature being 

 given to the several tunics, and before their nature and origin 

 were inquired into. Gaertner, in the use of this term as applied 

 to Magnolia, explains that its testa is covered by a fleshy envelope 

 analogous in its nature to that of an arillus, and in describing 

 the seed of that genus, he defines its envelopes as consisting of 

 three distinct tunics ||. Drs. Hooker and Thomson had in the 

 meanwhile adopted tiie opinion of Dr. Gray regarding the outer 

 seed-coats of Magnolia, and in this respect they difl'er from all 

 preceding botanists^. 



* Linn. Trans, xxii. 89. % Gen. Unit. States, i. CO. 



t Linn. Trans, xxii. § Hook. Kew Journ. vii. 244. 



]| De Fruct. Intr. 133; vol. i. 343; Linn. Trans, xxii. 86. 



i[ This is denied by the reporter, in a marginal note made on my paper; 

 but, with all the consideration due to that authority, I submit, as far as my 

 memory- extends, that I know of no one who has j)reviously entertained 

 the opinion of Dr. Gray, that this scarlet coating is the testa. Gaertner's 

 definition, here alluded to, is dated 17^8; and those who subsequently 

 adopted the same expression would have explained their meaning, if they 

 differed from that definition. Jussieu, however (1789), distinctly confirms 

 Gaertner's explanation (Gen. PI. 281), when he ascribes to Magnolia 

 " semina baccata sou arillata." DeCaudoUe, in his ' Systema ' and ' Pro- 

 dromus,' adopts simply the same jihrase " semina baccata," without further 

 explanation. Spach fPhaner. vii. 4(59) says positively "arille charnu." 

 Kndlichcr (Gen. PI. 4737) also defines it " integumcntum extcrius cainosum 



