248 AMENTA LES. [Diclinous Exogens. 



Alliance XVIII. AMENTALES. — The Amental Alliance. 



Diagnosis. — Flowers diclinous, in catkins, achlamydeous or monochlamydeous ; carpels 

 superior ; embryo small, with little or no albumen. 



About the near alliance of the mass of genera here collected, no reasonable doubt can 

 be entertained; and, in fact, they are associated in almost all systems of classification. 

 Their strictly unisexual flowers, amentaceous inflorescence, and incomplete calyx, 

 afford the most obvious marks of identification. To this, however, die Order of Oleasters 

 offers an exception ; those plants are almost universally referred to the vicinity of Daph- 

 nads (Thymelacese), among Perigynous Exogens, because the Elseagnus is taken as the 

 type of their structure. I confess, however, that the latter genus seems to be far from 

 offering a correct idea of this peculiar Order, which is much better represented by 

 Hippophae and Shepherdia. Indeed, it is open to question whether the genus Elseagnus 

 itself would not fall more properly into the ranks of Daphnads. Upon that supposition, 

 no doubt could be entertained of Oleasters finding their most natural station here. 



Independently of the relations borne by Beefwoods (Casuarinaceae) to the Joint-firs 

 among Gymnogens, it is evident that other strong lateral affinities present themselves. 

 These are more especially manifest between Liquidambars and the Planes of the Urtical 

 Alliance, and between Galeworts and the Crowberries of the Euphorbial Alliance. 



If we attempt to trace a passage from Order to Order in the Alliance itself, it will be 

 observed that the winged fruit of Beefwoods is of the same nature as that of their suc- 

 cessors the Birchworts ; that the latter are imitated by the Liquidambars, which may 

 be almost regarded as polyspermous Alders. If we suppose the two carpels of Liqui- 

 dambars to lose their partition, and the seeds to be covered with hairs, Willowworts 

 would be the result of the change. At this point the series is interrupted, for there is 

 nothing at present known to connect either Galeworts or Oleasters with Willows ; these 

 Orders are rather to be regarded as a modification of Beefwoods and Birchworts, by the 

 substitution of a fleshy for a membranous pericarp. Their true relation will be best 

 expressed thus : 



Joint-firs. 



Beefwoods — Birchworts — Liquidambars — Willowworts. 



Galeworts. 



Oleasters. 



Natural Orders of Amentals. 



Ovary I -celled. Ovule 1 or 2, ascending. Radicle superior . . . 77. Casuarinaceae. 



Ovary 2-celled. Ovule 1, pendulous. Radicle superior 78. Betulace.£. 



Ovary 2-celled. Oi'ules 00. Seeds winged 79. Altingiace.*. 



Ovary \-eellcd. Ovules 00. Seeds cottony 80. Salicace^e. 



Ovary 1 -celled. Ovule 1, erect. Radicle superior 81. Myricace^e. 



Ovary l-celled. Ovule 1, ascending. Radicle inferiw 82. El.eagnace.e. 



