including a new Arrangement of Phanerogamous Plants. 193 



be made, and transition-classes, not strictly referable to either of 

 the two primary divisions, must be expected, such as Berberidese, 

 Morese, and Mimosese. The latter remark however applies prin- 

 cipally to the Proterocarpous Division, as in the Heterocarpous 

 Division the position of the single carpel is in all probability 

 variable and nearly in the same degree throughout the Orders : 

 thus its position in the Orders of the Anonal Alliance must be 

 expected to be variable, as in Tasmannia, in those of the Clusial 

 and Anacardial Alliances, as in Anacardiaceee, &c. And the 

 remaining inquiry therefore appears to be more especially as to 

 whether the Orders included in the Proterocarpous Division have 

 the single carpel always anterior or lateral, or with so few excep- 

 tions as that they might be associated with them. 



It is worthy of remark, that although the position of the car- 

 pels when two may be variable to the greatest degree in a single 

 genus, as in Ribes, yet, on the other hand, it does not separate 

 genera, which Jussieu's and other systems would, if strictly ad- 

 hered to ; thus, the position of the two carpels is the same in 

 monopetalous, polypetalous and apetalous Oleacese, as also in the 

 perigynous Eschscholtzia and hypogynous Glaucium. 



But the position of the carpel when single does not appear 

 liable to such exceptions, and may assist in determining affinities 

 which at present remain much obscured ; thus, its position in 

 Ceratophyllum corresponds with that of the Piperal Alliance, and 

 differs, as far as is at present known, from that of any other 

 Orders with which it could be associated, unless it is compared 

 with Nelumbium. 



It constitutes a differential character between families other- 

 wise scarcely distinct, as does also in some cases the position of 

 the fertile cell of compound ovaries ; thus. Viburnum differs from 

 Centranthus, Valeriana, Valerianella and Fedia, whether the axis 

 or (in the latter genera) the irregularity of the corolla is re- 

 garded, or the position of the stamens in Fedia (see also Part 

 III. and the accompanying figures). 



Two-celled Ovaries with Unequal Cells. 



When the two cells of an ovary are equal in size, each con- 

 taining an ovule, and the fruit becomes one-seeded, the position 

 of the fertile cell cannot be relied on as an indication of the po- 

 sition the single carpel would occupy. Thus, in Galenia africana 

 the ovary consists of a single carpel anterior, but in a two-celled 

 one-seeded species (the carpels being anterior and posterior) 

 either cell indifferently is fertile ; and this deserves more atten- 

 tion, because in the nearly allied genus Trianthema, a one-celled 

 species {T. mio^antha) occurs having the carpel anterior or less 



Ann. S^ Mag. N. Hist. Ser. 2. Vol. xi. 13 



