ON HIPPOCRATEACE.E. 221
2. In the former, the stamens are distinctly inserted inside the disk ; in the latter, they are invariably inserted outside the disk.
3. In the former, the anthers, generally of a peculiar form, are con- stantly extrorse ; in the latter, they are of the usually normal structure, and always introrse.
4. In the former, the disk is generally elevated, and presents a free wall of separation between the stamens and" more external parts ; in the latter, it is a mere expansion of the torus, intervening between the ovary, and all other floral parts.
5. In the former, the sepals, petals, stamens, and disk are persistent at the base of the fruit, and are never seen in such position in the latter family.
6. In the former, the superior ovary is always elevated above the torus, and quite free from it ; in the latter, it is always more or less partially imbedded in the disk, and half agglutinated with it.
7. The atrophied condition of the axis of the ovary, though not a con- stant feature, is one quite peculiar to the Hippocrateacere ; and on the other hand, in Celastracers we tind no growth at all approaching the several kinds of large drupaceous fruits seen in the Hippocrateacea:.
8. In the development of the seeds there is a constant distinction. In Hippocrateacece they are invariably without albumen ; in the CelaatracecB, the embryo, without exception, is enveloped in albumen, usually copious. In the former, the cotyledons are often closely conferruminated in a solid mass, a circumstance quite unknown in the latter.
9. In the Hippocrateacece no trace of an arillus can be seen; in Celas- traceee, though not universal, a distinct arillus in most cases partially sur- rounds one extremity of the seeds. In the former, in one tribe, the seeds exhibit a greater or smaller expansion of the testa, in the shape of a large membranaceous wing, or a narrower alar keel, while in the two others they are invested by an ariUine, an entire fleshy coating, the nature of which Mr. Miers explained many years ago, — a feature seen in some other fami- lies, though too often unnoticed by botanists.
10. In the Hippocrateacece, the leaves, but more particularly the branches of the inflorescence, the pedicels, sepals, petals, contain nume- rous white elastic threads, which hold the parts together when broken ; and these spiral threads often extend to the pericarps, to the integuments of the seeds, and even occasionally to the fleshy cotyledons. Nothing of this kind has yet been observed in Celastracece.
Any one of these peculiarities, by itself, would tend little to support any separation of these two families, but the sum of the whole tells power- fully to mark a great distinction in their organization. The only argu- ments that have yet been urged for their near affinity are that both generally consist of arborescent plants, with evergreen leaves, an axillary inflorescence, petals and sepals with imbricated {estivation, a 3-celled ovary, a simple style and stigma ; but these are all characters common to many other families, distantly related, and wholly insufficient by them- selves to establish any near affinity. The more probable inference is t^liat these two families should be separated by a long interval.
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