XXV.—HUGONIACEAE. Arn.
This is a very small order, consisting of a single genus, and so far as I am aware of as yet only four species. Dr. Arnott was the first to propose the separation of this genus as the type of a distinct order, and published it as such in our prodromus. Dr. Lindley has since adopted the order in his natural system of Botany, whence we may infer, that he considers it justly separated from those with which it had been previously associated, and indeed there can scarcely be any doubt on the subject, since, for the reasons stated by Dr. Arnott, it could not be associated either with Malvacece nor Chlenaceae.
I republish from the Prodromus Dr. Arnott's character and remarks, the correctness of which I have verified by again carefully comparing them with the plant.
Calyx without an involucel, persistent, 5-sepaled : sepals distinct, acute, unequal : the two exterior lanceolate, densely pubescent on the back ; another dimidiate-ovate, the straight side pubescent, the rounded side testaceous and shining ; the two inner ones roundish ovate and
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HUGONIA MYSTAX (Linn.)
suddenly pointed, testaceous and shining except the short pubescent point : aestivation imbricated, quincuncial. Petals hypogynous, 5, alternate with the sepals, shortly anguiculate : aestivation twisted. Stamens hypogynous, 10, all fertile : filaments united at the base into an urceolus, free and filiform above : anthers cordate-ovate, erect, 2-celled, opening by two longitudinal clefts. Torus slightly elevated, supporting the staminal urceolus and the ovary. Ovarium roundish, coriaceous, glabrous, 5 celled : ovules 2 in each cell, pendulous, collateral. Styles 5, distinct : stigmas slightly dilated and lobed. Fruit (a nuculanium) with a fleshy epicarp, enclosing 5 distinct, bony, 1-seeded carpels. Seeds pendulous. Embryo in the axis of fleshy albumen : cotyledons flat, foliaceous : radicle short, superior, pointing to the hilum.—Shrubs. Leaves alternate, or sometimes crowded and opposite near the flowers. Stipules 2, subulate. Peduncles axillary 1-flowered, often by abortion transformed into circinnate spines.
Affinities. The only genus referable here has been placed by De Candolle with doubt in Chlsenaceae, to which we cannot agree; that order having the calyx and gynoecium in a ternary, while the corolla and andrcecium follow the quinaiy arrangement. Kunth hesitatingly places it in Byttneriaceae and the tribe Dombeyaceae, and there is no doubt that the affinity is very great; it is now separated on account of the imbricate (not valvate) calyx, the ovules pendulous (not erect or ascending), and the radicle superior (not inferior), rather than invalidate the character of the order by its insertion. In many points it agrees with the character (but not the habit) of Qxalideas, forming another link between the group of Malvaceous orders, and the Geraniaceae. Arn.
Geographical Distribution. Of the four known species of the genus Hugonia, one is found in continental India, one in Ceylon, and two in the Mauritius. H. ferruginea though described by us as an Indian plant, I have never seen growing except in Ceylon, and there it appears as a trailing shrub, seeking support from the surrounding jungle.
Properties and Uses. Of these nothing certain is known. Rheede who figures H. mistax, and as usual, gives what information regarding its properties and uses he could collect, informs us that the bruised root is employed to cure inflammation, and against the bites of serpents, that it is also used as a febrifuge, and vermifuge, and that the bark is good against poisons. These statements, which are derived from native information, have not been confirmed by modern experience, at least so far as I have been able to learn.
I have in the course of this work repeatedly alluded to the tendency which some plants have of augmenting or reducing the number of pieces in the floral verticel, and thereby passing from one class to another of the Linnasan system. The accompanying plate presents an example of this change. The quinary order is the normal form of this genus, that is 5 sepals, 5 petals, a 5-celled ovary, and 5 styles and stigmas : but it will be remarked in the fruit cut transversely, that it has only 4 seminiferous cells in place of 5 the regular number. It is probable that each series of floral organs, the calyx, corolla, and stamens was, in that instance, deficient in a similar proportion, namely, one-fifth part.
No additions have been made to this order since the publication of our Prodromus.
EXPLANATION OF PLATE 32.
1. A branch of Hugonia mistax, showing the leaves, flowers and fruit—natural size. 2. Lower figure—Sepals and petals removed, showing the filaments united at the base into a short tube, upper one—the stamens removed to show the extent to which the filaments are united, and that they are alternately longer and shorter. 3. Sepals, ovary, style, and stigmas. 4. A fruit cut transversely, showing four seminiferous cells, and four empty ones alternating. The nuculanum consists of 4 or 5 partially united, 1-celled carpels, or nuts : the alternating cells in this figure are in the lines of separation, and are owing to a depression on the sides of the nuts.