103 



the degree of exposure. In exposed places they may be no longer than 6 to 8 

 inches and stand erect, while in sheltered parts they are 18 to 24 inches long 

 and bend with a graceful curve, giving the familiar rounded silhouette to the trees. 



Casuarina sfricta woodland is only a closed community in the most shel- 

 tered parts of 781 Hill. In other parts there is an underwood of various trees 

 or shrubs, e.g., Melaleuca parviflora, Leucopogon Richei, which mingle and 

 compete with the sheoak. The soil is coarse with a humus content of 139 per 

 cent., but has only a low water-retaining capacity. In places between the 

 granite boulders there is a considerable depth of soil. Frequently the "forest" 

 ends abruptly (pi. v., fig. 1), owing to the presence of some large exposure of 

 granite. Several such places occur on 781 Hill, and one passes at a step from 

 the climax to the earliest phases in the succession. In the woodland the ground 

 below the trees is covered by a litter of fallen branchlets, old fruits, or tree 

 trunks. The forest suffered several years ago by fire, but it is generally 

 regenerating well ; many seedlings and young trees of various ages occur. 



Mosses are common, but in January were quite dried up. Mr. L. Rodway, 

 C.M.G., of Hobart, kindly determined the following: Br\nim intermedium, 

 Tortula rnuralis (form with a cuspidate hair point), and (?) Acanthocladium, sp. 



Herbaceous plants of the most sheltered places are : — 



Cheilanthes tcnui folia Agropyriim scahrum 



Festuca bromoides Didiscus pusillus 



During the winter and spring no doubt others would be found, but at the 

 time of our visit they were not to be seen. These herbaceous plants disappear 

 on hotter or more exposed places, e.g., the west face of the summit of 781 Hill 

 and xerophytic perennials as Mesembryauthemiim aequilaterale replace them. 

 Several colonies of Senecio Cunninghamii were found in sheltered places on 

 781 Hill. This is a half-shrubby plant with lanceolate leaves 8-12 cm. by •8-1-2 

 cm. that are glossy above and glaucous on the lower-surface. It has a less 

 xerophytic appearance than any other perennial on the island. 



The vmdershrub flora varies with differing degrees of dryness and exposure. 

 Just below the summit of 781 Hill, on the north-east side, there is an open area 

 with bushes of Calythrix fetragona, found nowhere else on the island. The 

 most usual undershrub in the more sheltered places is Leucopogon Richei, which, 

 though it appears in the open shrub association described below, is not found in 

 the most exposed places of the Casuarina woodland. Other plants occasionally 

 associated with Leucopogon Richei are Dodonaea viscosa and Cassinia spectabilis. 



In more exposed places, e.g., the summit of 781 Hill, on East Hill, especially 

 at the col and on the lower slopes, Melaleuca parviflora appears as the 

 undershrub and even replaces Casuarina (pi. v., fig. 2). It develops a distinct 

 and more xerophytic community. Transitions were seen in many places, but 

 most clearly on slopes with a northern aspect (pi. iv., fig. 1). The fire, or fires, 

 referred to earlier appear almost to have destroyed the Casuarinas of the north 

 facing slope above the right branch of Main Creek. Melaleuca parviflora forms 

 a dense thicket in which only a few Casuarinas are present. On Southern Island 

 there is a small group of about half a dozen stunted Casuarinas growing on the 

 most sheltered part of the north side. This represents a small outlier of the 

 Casuarina woodland which has every likelihood of dying out, since none of the 

 trees were fruiting nor were any old fruits to be seen below them. 



II. Melaleuca parviflora scrub. 

 A mixed scrub community in which Melaleuca parviflora often attains the 

 size of a small tree occupies the foot of 781 Hill and other hills on Northern 

 Island (pi. iv., fig. 2). The plant is absent on Middle and Southern Islands. 



