258 URTICALES. [Diclinous Exogens. 



Alliance XIX. URTICALES. — The Urtical Alliance. 



Diagnosis. — Diclinous Exogens, with scattered monochlamydcous flowers, single superior 

 carpels, and a large embryo lying in a small quantity of albumen. 



The main distinction between this and the Amental Alliance consists in the presence 

 of albumen, and the flowers not being arranged in catkins. The former character, 

 however, fails in several instances, especially in some Artocarpads and Hempworts ; so 

 that in reality the amentaceous inflorescence is the only difference that can be at present 

 pointed out to separate two Alliances, which nevertheless appear to be really distinct 

 if regarded as wholes. They touch most closely among the Planes and Artocarpads, 

 which may be referred indifferently to the one Alliance or the other, for both have a 

 quasi-amentaceous inflorescence, and Liquidambars agree with Planes in having albu- 

 men, while Artoearpus itself is said to differ from the mass of its order in the want of 

 it. Artoearpus cannot however be separated from Ficus, nor Platanus from Artoear- 

 pus, and this seems to justify the place assigned to Artocarpads and Planes in this 

 arrangement 



The Orders themselves do not always rest upon such distinctions as a botanist would 

 wish to discover ; this is most especially the case with Hempworts and Morads, which 

 might very well be united. But they may be allowed to remain for the present, 

 because we really know so little about the plants of the Urtical Alliance, that any final 

 distribution of the genera must be premature. It is much to be wished that some one 

 would seriously examine the heaps of undescribed obscure plants related to this part of 

 the vegetable kingdom, to be found in all large herbaria ; it would be hardly possible to 

 render a more welcome service to systematical botany. 



So many plants of the Chenopodal and Silenal Alliances are $ <j? , especially of the 

 former, where Atriplex alone forms a large mass of exceptions to the usually structure, 

 that we must suppose this to be one of the most remarkable instances of contact between 

 the hypogynous and diclinous sub-classes. 



Natural Orders of Urticals. 



Radicle superior. Ovules twin, suspended. Embryo straight, i „« c , 



albuminous. Anthers 2-lobed, with vertical fissures . . ./ 

 Radicle superior. Ovule solitary, erect. Embryo straight, "I „ . T y 



albuminous. Juice limpid. Stipules small, flat ....}' 



Radicle inferior. Embryo cxalbuminous. Plumule many- ] ,. . „ 

 leaved, large . * }85. Geratophyllace 



Radicle superior. Ovule solitary, suspended. Embryo hooked, 1 „.. „ 



cxalbuminous ? } 86. Canhabuuce*. 



Radicle superior. Ovules solitary, suspended. Embryo hooked, 1 .- M 



albuminous. Juice milky . J 



Radicle superior. Ovule solitary, erect or suspended. Embryo'] 



straight, cxalbuminous. Juice milky. Stipules large, con- 1 88. Artocarpace^e. 



volute J 



Radicle inferior. Embryo albuminous. Plumule minute. 1 „„ p 



Juice limpid. Stipules large, deciduous J LATA A E '• 



VCE.E. 



