42 THE VICTOKIAN NATURALIST. 



S. submanfeldtii, forma (?) ... Cheltenham 



S. brevispina ... ... Cheltenham 



Onychonema nordstedtiana ... Yarra (lagoon) 



Desmidium swartzii ... ... Heidelberg 



ON CERTAIN SUPPOSED NEW AUSTRALIAN PLANTS. 



By Alfred J. Ewart, D.Sc, Ph.D., F.L.S., Government 

 Botanist. 



{Read before the Field Naturalists' Club of Victoria, 9th A-pril, 1906.) 

 In the Victorian Naturalist for July 1900 (vol. xvii., pp. 39, 40), 

 the late Mr. J. G. Luehmann, F.L.S., mentions a new Cary- 

 ophyllaceous plant as Arenaria axillaris, but without giving any 

 description of it then or subsequently. Specimens of the plant 

 remained in the National Herbarium, and, curiously enough, 

 another incomplete specimen named, Arenaria axillaris, from 

 Syria, and with the inscription, " Presented by La Billardiere," has 

 been found there. No authority is given for this latter plant. 

 Its name is absent from the " Kew Index," and, apart from the 

 fact that both have axillary flowers, the two plants are strongly 

 dissimilar. The latter plant bears no resemblance to A. acicularis 

 {A. juniperina), but might possibly be a variety of A. tenuifolia 

 [A. arabica) with axillary flowers. 



This special peculiarity is not in itself sufficient to establish a 

 new species, when a plant which normally bears terminal cymose 

 clusters of flowers is found with its flowers arising in an apparently 

 axillary fashion on the vegetative axis. A tendency to a change 

 of this kind may be shown by many plants with diffuse terminal 

 inflorescences when growing under conditions favourable to 

 exceptional vegetative activity, as after a bush fire followed by 

 rain, or when a plant is repeatedly cropped, so that the growth- 

 tendencies are transferred to the lower nodes. 



Luehmann's specimen appears, however, to differ in other 

 points also from any species hitherto recorded, and hence the 

 following description of it may be published. The species must, 

 however, be regarded as a provisional one until either the plant 

 has been repeatedly collected from several localities or its seed 

 germinated and its life-history followed through several gener- 

 ations, under as widely different conditions as possible. If a 

 simple rule of this kind were generally adopted the number of 

 false species would be very greatly reduced, and possibly also 

 many of the larger and more diverse genera would be found to 

 contain fewer distinctive type species than is generally imagined. 



Arenaria axillaris, Luehm. 



A weak decumbent annual, more or less tufted at the base, 

 with straggling stems bearing leaves and axillary stalked flowers. 



