MR. D. OLIVER OX AURANTIACE3!. 3 



belonging to three or four genera. Nevertheless I consider that 

 it is in the genus Citrus, or at any rate in the group Citrece, that 

 the maximum departure, not of aberrant character, from all other 

 ordinal types is obviously attained. 



The Citrem are a little abruptly separated from the rest of 

 Aurantiacece. There are, however, remarkable bonds of union in 

 two species from Eastern Asia, one of which I consider must for 

 the present remain in Atalantia (A. Hindsii) ; the other, half 

 Citrus, half Atalantia, may perhaps be regarded of generic mark, 

 though, in the absence of fruit, I have not ventured to describe it 

 under a new name. The genera which it immediately connects 

 seem too far removed to admit of its being appended to either 

 without very unduly weakening their diagnostic formulas; to 

 maintain which without sacrificing too greatly the conception of 

 a natural group, is as essential to their practical utility as is the 

 maintenance of natural generic assemblages as resting-points for 

 the philosophical study of plants. It is through the genera Ata- 

 lantia and Paramiqnya (unifoliolate groups), and Feronia, that the 

 true oranges further link themselves with the larger, 3-multi- 

 foliolate section of the order. The tendency so common in Citrus 

 to union, more or less, of the filaments is noticeable in two genera, 

 Atalantia and Luvunga ; the former with collateral, the latter with 

 superimposed ovules. Atalantia manifests a further affinity to 

 Citrus in its shining unifoliolate leaves and general primd facie 

 features. The increased number of stamens in A. Hindsii, and 

 their irregular polyadelphous condition, indicate yet more their 

 mtimate relationship. In all the remaining genera of Aurantiacece, 

 apart from Citrea?, I find the filaments constantly free. 



From the position of the Aurantiacece in the classificatory se- 

 quence of the ' Prodromus,' the order was among the earliest pub- 

 lished in that important work (in vol. i. p. 535). M. DeCandolle'B 

 materials were limited, and as the discoveries which have since been 

 made are numerous, his monogi'aphy is now comparatively useless. 

 He describes thirty -four species, exclusive of incerta?. Blume's 

 important descriptive contribution appeared in 1825 in his ' Bijdra- 

 gen tot de Flora van Nederlandsch Indie:' he confines himself to 

 the species growing in Java, wild or cultivated, of which he pub- 

 lished two new genera — Sclerosti/lis and Micromelum. The diffi- 

 culty of clearing up my doubts by a sight of authentic specimens 

 of Blume's species has pressed upon me, and is perhaps the chief 

 reason why I have not aimed at a more complete monograph of 



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