Hill and Johnson, Eucalyptus (Myrtaceae) 
527 
Distinguished from the type subspecies by the smaller and more delicate leaves, buds 
and fruits. 
Distribution: north and east of Gibb River station in Western Australia, not extending 
east of the Durack Range (Fig. 11). 
Ecology: restricted and highly localised, usually on alluvial sandy soils near creeks. 
Conservation status: although of rather restricted distribution and not abundant 
within its range, this species occurs in a habitat that is not significantly threatened (3R). 
The epithet is from the Latin modicus , moderate-sized, from the smaller sizes of all 
parts of this subspecies in contrast to the type subspecies. 
Selected specimens (from 6 examined): Western Australia: 13 km W of Berkeley R, Brooker 7778, 
2 Nov 1982 (CANB, NSW); 7.2 km W of King George R crossing on track to Carson R., Hill 953, 
Johnson & Benson, 25 July 1984 (NSW); 'Gibb River' Station near Homestead, Johnson 2090 ,26 Aug 
1967 (NSW); 50 miles 182 km] NNW of Gibb R. Station, Speck 4977 ,10 Sep 1954 (CANB, NSW). 
Subseries Tectificosae 
Bark fully persistent. Adult leaves lanceolate. Fruit chartaceous, dehiscing 
immediately on maturing. Seeds grey-brown to dark grey-brown. 
A subseries of two species occurring in grassy savanna country in north-western 
Queensland and the north of the Northern Territory and Western Australia. 
Key to species 
1 Fruits smooth, 4—6 mm long, 4—5 mm diam. E. tectifica 
1* Fruits ribbed, 6-8 mm long, 5-7 mm diam. E. costuligera 
9. Eucalyptus costuligera L.A.S. Johnson & K.D. Hill, sp. nov. 
Ab E. tectifica distinguitur: folia alabastraque glauca, alabastra fructusque longiores et 
costati. Habitat sola sicca, saxosa aliquantum elevata. 
Type: Western Australia: 60 km E of Gibb River to Kalumburu road on Wyndham road 
(16°20'S, 126°55'E), M.I.H. Brooker 7780, 3 Nov 1982 (holo NSW; iso CANB, PERTH). 
Tree to 10 m tall. Bark persistent throughout, pale grey, shortly fibrous-flaky (box). 
Adult leaves disjunct, similifacial, lanceolate, obtuse, 70-150 mm long, 17-30 mm 
wide; petioles to 22 mm long; lateral veins ± closely-spaced, regular, at 40-60° to 
midrib; reticulum even, dense; oil glands small, dense; intramarginal vein continuous, 
distinct, <0.5 mm from margin or at margin. Inflorescences compounded, 
pseudoterminal or axillary; unit umbellasters 1-7-flowered, somewhat irregular. 
Peduncles terete, 1-15 mm long. Pedicels terete or ± ribbed, 2-6 mm long. Mature buds 
clavate, apiculate, regularly shallowly ribbed; c. 7 mm long, c. 4 mm diam.; calyptra 
broadly hemispherical, apiculate to rostrate, c. 1/2 as long as hypanthium. Fruit 
cylindrical to cup-shaped or pyriform, apically constricted, ± chartaceous, often 
regularly shallowly ribbed, 3-4-locular, 6-8 mm long, 5-7 mm diam., deciduous at 
maturity; calyptra scar and stemonophore flat or somewhat depressed, <0.5 mm wide; 
disc vertically depressed, 1-2 mm wide; valves broadly triangular, obtuse, wholly 
enclosed, vertically raised, ± chartaceous. (Fig. 12). 
Eucalyptus costuligera differs from E. tectifica F. Muell. in the more coriaceous, glaucous 
leaves and buds, the longer, ribbed buds and fruit, and the differing habitat, on 
elevated, dry, shallow, stony soils. 
