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No. 35: Eucalyptus punctata,

DC

A Grey Gum

(Natural Order MYRTAGEÆ.)

Botanical description

— Genus, Eucayptus. (See Part II, page 33)

Botanical description

— Species, E.punctata, DC.

Branchlets. — Robust and very angular.

Leaves. — Scattered, elongate or sickle-shaped lanceolar, of thin consistence, beneath slightly paler and there not shining; the lateral veins numerous, very subtle, and much spreading, the circumferential vein close to the edge; oil dots numerous, imperfectly transparent; umbels axillary and solitary, or, at the summit of the branchlets paniculated; their stalks broad and strongly compressed, bearing generally from three to ten flowers.

Calyx-tube. — Almost semiovate or nearly hemispherical, merging gradually into an angular, rather thick, stalklet, of about the same or greater or lesser length.

Opercculum. — Semiovate conical, as long as the tube or somewhat longer.

Stamens. — All fertile, inflexed before expansion ; anthers almost oblong, but upwards broader, opening with longitudinal parallel slits.

Stigma. — Not or hardly broader than the style.

Fruit. — Nearly semiovate, three or oftener four, rarely five-celled, not large nor angular, rim finally rather broadish, flat, or convex; valves short, deltoid, at last exserted or convergent from the rim. (Mueller, in "Eucalyptographia.")

Variety grandiflora, Deane and Maiden (Proc. Linn. Soc., N.S.W., 1901, p. 133). This is a large-flowered and large-fruited form.

Leaves punctate. Buds all ovoid. Double operculum. Rim at junction of calyx and operculum very sharp. The calyx-tube usually angled. Fruits, 7 to 8 lines in diameter. Valves usually not much exserted.

I have an intermediate form (from Wyee), with valves well exserted; shape hemispherical, or nearly so, to conoid. Rather broad rim. Bark and timber not to be distinguished from that of normal punctata. This large-fruited form is wellmarked, and well worthy of being a named variety. As in resinifera, so in punctata, there is no line of demarcation between the normal and grandiflora forms, the transition being gradual.

Comparing this with the normal or small-fruited form, Mr. Augustus Rudder, a forester of considerable experience, writes in the Agricultural Gazette:—

This is one of two trees with the same vernacular (Grey Gum). In general appearance, to the casual observer, the trees are much alike, but the leaves of this are rather broader, and its fruits and


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blossoms are very much larger than those, of the other variety and the trees generally are not so large, and are more limited in range of habitat, and, as a rule, do not approach so near to the coast, though I have seen it at Raymond Terrace; and near the beach at Charlotte Bay and Wallis Lake, in this district, the two trees often grow together. I have mostly observed it on the lower ranges in the counties of Gloucester and Durham. The timber is red in colour, is hard and very lasting, and is well suited in the round for heavy timbers in bridges and culverts.

I have personally collected it within the range stated. Hitherto this form has only been found north of Port Jackson.

This tree has been frequently confused with the grandiflora form of Eucalyptus resinifera, where herbarium specimens only are available; in the forest the two trees could not be confused for a moment, their bark immediately distinguishing them. The buds also are very different, those of the variety of punctata being, as already indicated, ovoid,note and the rim very sharp, with frequently a double operculum, while that of the variety of resinifera being conical and even rostrate.

The fruits of the variety of resinifera have the valves more exserted, and they sometimes have a tendency to be conical.

Messrs. Baker and Smith (Research on the Eucalypts, p. 128) have evidently overlooked this, and have renamed it var. major, stating —

This is a variety with larger fruits and flowers, and, as far as known, occurs only at Booral New South Wales. — (A. Rudder.)

The same gentlemen (op. cit., p. 127) describe a var. didyma:—

This variety is distinguished from the type by its having two opercula to each bud, and by the difference in its oil. The outer operculum is thin, and is shed very early in the budding stage, so that it is scarcely ever to be found in herbarium material. The fruits always have a broad groove below the rim, and the leaves are also larger and thicker than those of the type, while the wood is also more open in the rain and less interlocked. Otherwise, morphologically, there is little to distinguish it from the type.

It seems a pity to endeavour to establish a variety on such slender morphological grounds.

Botanical Name

— Eucalyptus, see Part II, page 34; punctata, Latin, dotted. In the original description it is stated, "Dots on the under surface of the leaves blackish." These blackish dots are almost invariably present; often the aid of a lens is required to see them properly. They are, however, not characteristic for punctata, being often present in Eucalyptus resinifera and other species.

Vernacular Names

— Botanists are often blamed for not giving one common name, and one name only, to one particular species of Eucalyptus, and when it is suggested that there are difficulties in the way, such a suggestion is attributed to perverseness. I am afraid the millenium will have arrived before the reform hinted at can be carried out. The present species is a good one for illustrating one of the reasons why the "one species one common name" dictum cannot be realised. More than one other species is known as Grey Gum, for


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example, Eucalyptus propinqua and Eucalyptus tereticornis. Then why another Grey Gum? Suppose we call Eucalyptus tereticornis Red Gum (a name by which it is frequently known) instead of Grey Gum; then there will be more or less confusion between it and its brother, Eucalyptus rostrata, the Red Gum par excellence. Or, to come back to the subject of our present Grey Gum, suppose we suppress Grey Gum, having assigned that designation to Eucalyptus propinqua, then there remains the next best and most used name for it, which is Leather-jacket. But consider the number of other trees which have a vested interest in the name of Leather-jacket, which have indeed more claim to the name, because of greater appropriateness and use by a larger number of people, and we at once see that if we appropriate the name for Eucalyptus punctata we shall be as far of our "one species one name" as ever. The fact of the matter is, that so long as people are so obstinate as to please themselves in the matter of names, and so long as the same object presented to different individuals is seen by them in different aspects, so long will this name difficulty continue. The Grey Gum people will not give up their name simply to please the Red Gum people, and so on. The former say: "Our name is the more suitable; we look at the bark,-see how grey it is." The latter say But look how red the timber is."It is of no use to blow up the botanist. He does not give the local names. The people at large do that, and who can control them ? The chief reason why we give "botanical names" is in order to obtain a definiteness not obtained by vernaculars. Some of our species have at least eight or ten common names.

The term Grey Gum is applied to punctata because of the dull grey appearance of the bark. The bark has a roughish appearance, in contradistinction to a smooth and even shiny one, possessed by so many of our gums. It has smooth, white patches in places, caused by the outer layer of bark falling off. These white patches in their turn become grey, and the process of exfoliation of the bark is repeated until probably the whole of the bark on the trunk is shed at one time or another. Although rather difficult to properly describe, the bark of the Grey Gum is so characteristic that, when once pointed out, it could not be confused with the bark of any other hardwood tree.

It is called "Black Box" at Capertee, owing to the darkness of the bark, and Mr. Forester Sim, of the same place, says it is also called "Slaty Gum." The smooth bark is sometimes of a yellow ochre or pale brown colour, hence it might then be appropriately called "Brown-barked Gum."

Aboriginal Names

— George Caley, the botanical collector for Sir Joseph Banks, stated — 9th February, 1807 — that "Mandowe," or "Mundowey," was the name given by the blacks of the Sydney district. It is interesting to note that, half a century later, Sir William. Macarthur gave the name "Maandowit," as the aboriginal name of the Camden blacks, for the local Grey Gum.

Synonym

— Eucalyptus tereticornis, Sm.; var. brachycorys, Benth. (B.Fl. iii, 242).




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Leaves (Oil)

— Messrs. Baker and Smith (Research on the Eucalypts) give the following particulars in regard to the oil of this species, and of the so-called variety didyma:—

     
Species.  Specific gravity at 15°C.  Specific rotation, [a]D  Saponification number.  Solubility in Alcohol.  Constituents found. 
E.punctata  0.9129 to 0.9922  -2.52° to +4.44°  18.78  1 1/4 Vols. 70%  Eucalyptol, pinene, aromadendral. 
E.punctata var. didyma.  0.9033 to 0.907  -4.63° to -6.53°  10.9 to 11.6  7 vols. 70%. to vols. 80%.  Eucalyptol, pinene, aromadendral. 

Flowers

— Large handsome flowers, with a sour offensive smell like sour gum arabic.

Fruit

— Attention is directed to the fact that this is one of the species displaying considerable variation in the size and shape of the fruit.

Bark

— It belongs to the smooth-barked group of gum-trees, and yet as compared with the silky smoothness of the White Gum (hæmastoma), or of the Blue Gum (saligna), its bark is raspy to the touch. As a whole, its trunk may be said to have a dirty appearance, often inclining to a yellowish or brownish cast. Large pieces of thin, dark-coloured outer bark give it a blotched appearance. I have already alluded to this in speaking of "Vernacular names."

Timber

— It is so much like Ironbark in appearance that it is difficult to discriminate between the two timbers. That will be the best guide to its appearance. An expert would usually detect the substitution for Ironbark (if lie suspected any substitution), by noting that a chip of Grey Gum is more brittle than that of Ironbark; it also cuts less horny. Nevertheless, the two timbers are wonderfully alike, and for many purposes Grey Gum is an efficient substitute for Ironbark, for it is remarkably durable. Its inferior strength, as compared with Ironbark, precludes its use as girders of any length, and when substituted for Ironbark in sleepers the bolts and spikes work loose in them. I would encourage it use in every possible way for wood-blocks. The chief objectors to its use at the present time are the saw-millers themselves, as the logs often contain gum-scabs or gumveins. At present, where unblemished timber is insisted upon for wood-blocks, a saw-miller cannot afford to cut up Grey Gum (although it frequently turns out unblemished), because of the risk of having it condemned. I will speak on this subject in connection with Bloodwood, and would emphasise the opinion that woodblocks should not be condemned becausethey contain a few gum-scabs or veins. Such excess of care practically leads to great waste of really valuable timber. It is recommended for paying-blocks, as already stated. It is in high repute for posts, having excellent records when employed in this very trying situation. I have seen it used for felloes and for shingles. It is very largely used as an Ironbark substitute for railway sleepers, which fact is in itself testimony to its excellence.




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The use of shingles in this State is borrowed from England. In Gilbert White's Natural History of Selborne, at Letter IV of the "Antiquities of Selborne," he speaks of their value and durability for roofing in the following passage:—

The whole roof of the south aisle, and the south side of the roof of the middle aisle, is covered with oaken shingles instead of tiles on account of their lightness, which favours the ancient and crazy timber frame. And, indeed, the consideration of accidents by fire excepted, this sort of roofing is much more eligible than tiles. For shingles well seasoned, and cleft from quartered timber, never warp, nor let in drifting snow; nor do they shiver with frost; nor are they liable to be blown off, like tiles; but, when nailed down, last for a long period, as experience has shown us in this place, where those that face to the north are known to have endured, untouched, by undoubted tradition, for more than a century.

Exudations

— (a) Astringent: This tree yields a dark brown kino, which (amongst the kinos already known) is perhaps characteristic. When freshly exuded it has much the colour and viscosity of molasses, and has a somewhat vinous odour not easily described. In the course of a day or two it solidifies into a friable mass. It is highly astringent. (b) Saccharine: The Rev. Dr. Woolls first drew attention to the existence of manna in this species. I have seen manna on this tree frequently, but only on the edges of leaves which have been eaten by some insect.

Mr. H. G. Smith,note however, records (and gives a full account of) a saccharine exudation whose origin does not appear to be clear. "When exuding it must have been liquid, as it had run down the tree." The material obtained was more or less mixed with bark and debris, caused by boring beetles. An exudation of this character is very interesting, and I only know of one other instance of the kind, i.e., where a saccharine mass from Eucalyptus Stuartiana, Dalgety, Snowy River, was sent to me a few years ago. Mr. Smith's analysis is ample, but we require further investigation in regard to the physiological aspect, i.e., the way in which sugar in such large quantities has been manufactured, and has exuded from the tissues of the plant.

Size

— A tree of large size, although not of the largest. Its height may be given as, say, 60 to 80 feet, with a diameter of 2 or 3 feet.

Habitat

— It appears to bc confined to New South Wales. It is found in the coast districts and main dividing range and spurs. Conjola, near Milton, appears to be the most southerly locality recorded. In the north it has been collected as far as Lismore. In the west it occurs near the Jenolan Caves, at Capertee, and Rylstone.

EXPLANATION OF PLATE 37

Plate 37: A Grey Gum (Eucalyptus punctata, DC.) Lithograph by M. Flockton



  • A. Sucker leaf.
  • B. Flower-bearing twig,
  • C. Fruits.
  • D. Fruits of variety grandiflora, Deane and Maiden.

Footnotes Issue No. 35

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