NOTICES OF BOOKS. 189 
there is any tangible feature by which they can be separated as species ? 
or any characters which would not in other cases be considered mere 
modifications of one and the same form ? 
On the Affinities of the Genera Vavma, Benth., and RHYTIDANDRA, 
Gray; dy Prorzssor Asa Gray, of Cambridge University, Boston, 
U.S. Communicated to the American Academy of Natural Sciences, 
October 10, 1854. 
In this paper Dr. Gray has ably discussed. the affinities of two very 
obscure plants belonging to the Polynesian Flora, and of which imper- - 
fect specimens only had hitherto been described. Of these, Vavea 
(after the Island of Vavao, one of the Friendly group), was discovered 
by Mr. Hinds, and first described by Bentham (Journ. Bot. vol. ii. 
p- 212), but from too incomplete data to admit of its immediate rela- 
tionship being discovered. The same plant was afterwards gathered 
by the officers of the United States Exploring Expedition, and more 
fully described by Gray in the Botany of that Voyage (vol. i. p. 244, 
t. 16), where it was appended to Meliacee, notwithstanding its stamens — 
being incompletely united, and double or triple the petals in number. 
Additional specimens from the same sources now enable Dr. Gray to 
show that the anomalies in question are mainly due to the flowers being 
polygamous, and that the fruit is entirely conformable to that of the 
Tribe Trichiliee of Meliacee. 
In some observations appended to this genus, Dr. Gray proceeds to _ 
discuss the affinities between Meliacee and Styracee, the subject being — 
suggested by the circumstance of Mr. Rich, the botanist to the Expe- = 
dition, having ticketed and figured Vavea as a species of Styrax ; and js 
he adds some remarks upon Mr. Miers’ proposal to separate Styraw — 
widely from the Symplocinee, whilst that author ignores any affinity — 
between Styracee and Meliacee, and includes Pamphilia and Faveolaria — 
in the former. In some copious notes (whose number and length how- — : 
ever tend to involve this very obscure and important subject) Dr. Gray — 
diseusses all the points of fact and theory upon which he differs from Zs 
Mr. Miers, displaying a perfect familiarity with the Natural Orders in. 
question, and with the structure and anatomy of their contained and — 
allied genera, and a sagacity in interpreting their characters and reveal- - 
ing their affinities which is quite admirable. 
