EUCALYPTUS 



Eucalyptus, L'116ntier; Sertum Anglicum, i8, t. 20 (1788); Bentham and Mueller, Flora Austra- 

 liensis, iii. 185 (1866); Bentham et Hooker, Gen. PI. ii. 707 (1876); F. von Mueller, 

 Eucalyptographia, decades i.-x. (1879-1884) ; Naudin, in Ann. Sc. Nat. xvi. 337-43° (1883), and 

 Descript. Emploi Eucalpt. Europe, 1-72 (Antibes, 1891); Masters, in Gard. Chron. xxi. 148 

 (1884), and ix. 176 (1891); M'Clatchie, U.S. Dept. Agric. Forestry Bulletin No. 35, pp. 1-106 

 (1902); Maiden, Revision Genus Eucalyptus, i. 1-24 (1903); Ingham, Agric. Exper. Station, 

 Berkeley, California, Bulletin No. 196, pp. 1-114 (1908). 



Evergreen trees or shrubs, belonging to the order Myrtaceae. Bark on young trees 

 smooth and peeling off; on old trees variable — {a) remaining smooth ; {b) persistent 

 and rugged at the base, but smooth on the upper part of the trunk and on the 

 branches ; {c) persistent and fibrous ; {d) persistent, very hard, and deeply furrowed ; 

 or (e) persistent and dividing into separate scales on the trunk. 



Leaves on young plants beyond the seedling stage, and also on suckers, opposite, 

 horizontal, sessile, cordate : variable on adult trees, {a) in some species, remaining 

 always opposite, horizontal, sessile, and cordate ; [b) in other species, becoming 

 alternate and stalked, after the first six or eight leaves on the seedling ; or {c) in 

 most of the species, remaining opposite for several years, subsequently becoming 

 alternate and stalked. Usually the alternate leaves are similar on both surfaces, 

 with the stalk twisted, so that the blade is placed in a vertical or oblique plane ; 

 but in a few species the upper surface of the alternate leaves is darker in colour 

 than the lower surface, the petiole not being twisted, and the blade remaining in 

 the horizontal plane. Leaves nearly always glabrous,^ odorous, with pellucid or con- 

 cealed oil-dots ; venation pinnate, the branches always converging to an intra-marginal 

 vein, which is either close to or at some distance from the edge. 



Flowers usually in pedunculate umbels, rarely reduced to a single sessile flower ; 

 peduncles in most species solitary and axillary, or occasionally lateral at the base of 

 the current year's shoot below the leaves, or in some species, clustered in terminal 

 panicled umbels. Calyx of two parts : {a) the tube persistent, adnate to the ovary, 

 and truncate and entire (or rarely 4-toothed) after the fall of the (b) lid or 

 operculum, which covers the stamens in the bud. Petals none, unless represented 

 in a few species by a membrane under the operculum. Stamens numerous,^ inserted 

 close to the edge of the calyx in several rows, free or rarely united at the base into 

 four clusters, always deciduous ; all fertile or some of the outer without anthers ; 

 filaments thread-like, usually inflexed (rarely straight) in the bud ; anthers dorsifixed, 



' In the seedlings of a few species the leaves and branchlets are hairy. In a few species the stalk is inserted above the 

 base of the leaf, so that the blade is peltate ; but this condition only persists in the adult foliage of one species. 



' Kerner, Nat. Hist Plants, Eng. trans., ii. 107, 449, 782 (1898), points out that the walls of the capsules of the 

 Eucalypti are remarkably thick and strong, to protect the seeds against desiccation during long periods of drought. As, however, 

 no rain occurs when the trees of most species are in flower, the pollen is left quite unprotected. There is no corolla, and 

 the top of the calyx falls off, so that the whole of the stamens, often a hundred or more in number, are completely exposed. 



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