198 



From the foregoing tables it is seen that the climate is of 

 the semi-arid type/"^) though as the Franklins are islands the 

 conditions are naturally less severe than on the mainland. Mr. 

 Lloyd, owner of the lease, says that in his 40 years' experience 

 on St. Francis Island (one of the Nuyt's Archipelago group) 

 he has not known either a frost or a day of over 100° in the 

 shade. The atmospheric humidity, also, will be greater on 

 the islands than on the mainland. There was ample evidence 

 that wind-shearing had an important effect on the growth form 

 of the plants, and in killing back the exposed shoots of such 

 relatively xerophytic plants as OJearia axillaris and Calo- 

 cephaliis Brownii. 



As regards the rainfall (Table I.), it will be seen that 

 the records of both mainland stations show that no rain may 

 fall during seven months out of the year, and that the average 

 precipitation for the four months December-March is '50 in. 

 or less per month. 



Vegetation. 



Littoral Flora. — This may be considered under the head- 

 ing of fore-cliff vegetation and coastal dunes, but except on 

 the north coast is everywhere sparsely distributed. The main 

 fore-cliff vegetation is Coloce'phalus Broivnii, the individuals 

 of which form low roT:yided bushes, 1 ft. to 2'5 ft. high. The 

 branching is densely intricate, and the linear-cylindrical leaves, 

 3 mm, long, stand erect, parallel to the stems. The whole 

 plant is white in colour owing to the development of close 

 tomentose woolly hairs. In places, along the north coast 

 especially, and less frequently along the other coasts, such 

 bushes form a continuous line a yard or two wide, fringing 

 the shore, rooting in the coarse sand, and often protected on 

 the seaward side by granite boulders. Occasionally bushes 

 of Myoporum insular e and Nitraria Schoeberi are to be found 

 in association with the Calocephalus, when the strip of vege- 

 tation is wider. Both the Calocephalud and Myoporum showed 

 obvious wind-shearing, the twigs on the weather side being 

 cut back and dead. 



Other developments of a littoral flora, except in the case 

 of dunes, can be considered as being rather in the nature of 

 accidents than characteristics of the habitat. As such may 

 be considered the occasional patches of Frankenia pauciflora 

 developing at the foot of the cliffs in the sand that had 

 lodged behind a wide zone of granite boulders. More character- 

 istic of the littoral habitat was the development of a pure 

 sward of Sporoholus virginicus just above the high-tide mark 



(4) Cannon, W. A., Plant Habits and Habitats in the Arid 

 Portions of S. Austr., Carnegie Inst. Pnb., No. 308, p. 2, 1921. 



