A specimen of the botany of New Holland/Eucalyptus robusta
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Brown Gum Tree, or New Holland Mahogany.
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ICOSANDRIA Monogynia.
Cal superior, permanent, truncated, covered before flowering with an entire lid, soon falling off. Cor. none. Caps. of 4 cells, opening at the top, containing many seeds.
Lid conical, contracted in the middle. Umbels lateral and terminal; general and partial flower-stalks compressed.
THE genus of Eucalyptus, established by the celebrated French botanist M. L'Heritier, of whose fate amid the present dreadful convulsions of his country we have for some time been ignorant, was first published in the Hortus Kewensis, vol. 2. 157. The original species there mentioned is named obliqua, and a figure of it is given in M. L'Heritier's Sertum Anglicum, tab. 20; but the description has not yet appeared. Having lately received specimens from New South Wales of five more very distinct species, we shall now attempt to characterize them, first describing more fully that exhibited in our plate.
Eucalyptus robusta is one of the largest and loftiest of trees, frequently 100 feet in height; its wood hard, heavy and strong, of a reddish colour, and abounding with resin. Branches round below, covered with smooth bark, very angular towards the extremity. Leaves alternate, on footstalks, firm, smooth, with a strong rib and fine parallel veins, ovate, pointed, entire, generally oblique, and often a little unequal at the base, but not universally so. Stipulæ none. Umbels on flower-stalks, frequently from the axillæ of the leaves, and solitary, sometimes two or more together, forming a sort of alternate racemus, and sometimes such racemi terminate the branches. Bracteæ none. General flower-stalk an inch or more in length, compressed, two-edged, dilated upwards; partial ones about eight or ten together, nearly of the same form, but much shorter, single-flowered, dilated into the base of the calyx. Flowers yellowish, occasionally with a red tinge. Calyx obconical, sometimes round, often two- or even four-edged, entire; lid rather more than equal to it in length, swelling above the base, then suddenly contracted, and terminating in a blunt, slightly curved, conical point. When the lid falls off, it discloses numerous stamina, which soon spread very wide. The style stands on four cross ribs in the centre of the flower, which crown the germen; it is club-shaped, compressed or angular; stigma simple; germen in the bottom of the calyx. We have not seen the fruit ripe. Every part of this plant, and indeed of every other Eucalyptus we have examined, is void of all pubescence. This is not so highly aromatic as some other species, though very perceptibly so when rubbed, and it is likewise astringent and acrid. Its resin is an inferior sort of red gum, of a brown hue. The size and strength of the tree, like that of the European Quercus Robur, seem particularly to justify the name robusta.
EXPLANATION of TAB. XIII.
characters of some other species.
Lid conical, round, very smooth, thrice as long as the calyx. Umbels lateral, solitary.
The lid of this species is remarkably smooth and polished, not wrinkled even in the dry specimen; it often breaks off a little above the base, leaving its thin lower part like a loose ring round the calyx. The leaves are lanceolate.
Lid conical, and, as well as the calyx, angular, and somewhat two-edged. Heads of flowers lateral, solitary, on flower-stalks.
The leaves are ovato-lanceolate, firm, astringent, but not very aromatic. We have seen no other species in which the flowers stand in little dense heads, each flower not being pedicellated so as to form an umbel. The lid is about as long as the calyx. Flower-stalk compressed, always solitary and simple.
The fruit of this species, standing on part of a branch whose leaves are fallen off, is figured in Mr. White's Voyage, page 226, along with the leaves of the next species.
A fine essential oil, much like that of Peppermint, is obtained from this species, and every part of the dried plant exhales the same odour when rubbed.—We are now convinced this is distinct from the following, having compared the flowers of both. At the same time we have observed the minute white spots on the leaves (White's Voy. 228) in E. piperita, as well as in the other.
Lid hemispherical, with a little point. Umbels lateral, solitary; flower-stalks and young branches round.
Syn. E. obliqua, Ait. Hort. Kew. v. 2. 157. L'Herit. Sert. Angl. t. 20.
From the only specimen we have seen of this, which is in Sir Joseph Banks's herbarium, it appears the branches are all round to the very top. General flower-stalks round, the partial ones only slightly angular, not compressed. Bark rough from the sealing off of the cuticle, but this may be an unnatural appearance. Leaves ovato-lanceolate, aromatic, but without the flavour of peppermint.
Lid hemispherical, with a little point. Umbels panicled in a sort of terminal corymbus.
This, when in flower, is the most magnificent of its genus. The leaves are lanceolate, astringent and acrid, but scarcely at all aromatic. Flower-stalks all compressed. Lid somewhat membranous.
All the species are destitute of hairiness or pubescence, the leaves simple, lanceolate, or ovato-lanceolate, pointed, entire, most frequently oblique, and often unequal at the base, on angular footstalks, without stipulæ. Stamina very numerous. Style and stigma simple.
There seems to be another species in the gardens, with narrow leaves, the young ones of a rich purple, but its flowers are as yet unknown.