^^"J-'l CUAPMATS!, Impression of Fruit of Casuarina. oi 



volcanic field within a short period of time. As a matter of 

 fact, there probably existed a kind of intervolcanic flora, 

 establishing itself through the intermittent phases of the 

 volcanic activities of this presumably Pleistocene period. 

 Considerable light is thrown on this question by Dana's evidence 

 from the present-day lava-fields of Kilauea and Mount Loa, 

 which would suggest the proximity of the rough scoriaceous 

 type of flow known as " aa " alongside the smooth lava-flow, 

 and, perhaps linked up by the intermediate form, the ropy 

 lavas. In his " Characteristics of Volcanoes," 1890, p. 242, 

 J. D. Dana says : — " The ' aa ' field, owing to its crevices and 

 shaded recesses, retains moisture, and decomposition at surface 

 early commences, which favours germination of seeds ; and, 

 as I am informed by Mr. Baker, the stream often becomes 

 forest-covered when the pahoehoe alongside remains bare." 



An interregnum of a luxuriant flora during volcanic episodes 

 is well known in other parts of the world, as, for example, in 

 the familiar cases of the volcanic plateaus of Antrim, in the 

 north of Ireland, and of the Inner Hebrides. 



In this way we have revealed a great struggle for existence, 

 l)y the vegetation and other life of the lava-fields, waged 

 against the tremendous odds of a fierce volcanic energy, which 

 every now and again devastates whole districts of the 

 established vegetation. 



ON THE SIMILARITY OF BANKSIA SPINUWSA AND 



B. COLLIN A. 



By p. R. H. St. John. 



(Read before the Field Naturalists' Club of Victoria, 14th Sept., 1914.) 



Noticing the similarity of these two Banksias, I was induced 

 to make an investigation into their claim to rank as separate 

 species, and an examination of the plants in the forest and 

 those cultivated in the Melbourne Botanic Gardens warrants 

 the conclusion that they are identical. This result is well 

 supported by Mr. F. M. Bailey, F.L.S., Government Botanist 

 of Queensland, who remarks (" Old. FL," vol. iv., p. 1,360) : — 

 " The typical form of B. spimdosa. Smith, so far as at present 

 known, is confined to New South Wales ; but, from the 

 examinations of Queensland specimens of B. collina, and the 

 New South Wales one of B. spimdosa, I find nothing to keep 

 the two as distinct species." Referring to these remarks, 

 however, Mr. J. H. Maiden, F.L.S., Government Botanist of 

 New South Wales, concludes by saying : — " As far as New 

 South Wales specimens are concerned, the two species seem 

 to be sufficiently different " (" F. Fl. of N.S.W.," vol. iv., 

 part 8) ; but, in an additional note, he makes the following 



