86 Sargent, Westralian Form of Prasophyllum aiistrale. [^^^^'^-^^ 



A WESTRALIAN FORM OF THE ORCHID 

 PRASOPHYLLUM AUSTRALE. 



By Oswald H. Sargent. 



(Communicated by Prof. A. J. Ewart, D.Sc.) 



(^Read before the Field Naturalists' Club of Victoria, i6th June, 1913.) 



I FIRST met with this plant in a bunch of orchids exhibited in 

 a flower show in October, 1904. The specimens were im- 

 perfect, and, through an accident, were lost in drying. In 

 September, 1905, my brother found a solitary scape on a 

 gravelly bank of the York-Guildford road, about four miles 

 from York. I reported this erroneously as " P. cyphochilum (?)" 

 in the Journal of the W.A. Natural History Society, No. 3. 



In September, 1907, my brothers found many scapes on the 

 Helena road, off the York-Guildford road, about six miles 

 from York. I made a very thorough examination, and con- 

 cluded that the species must be Prasophyllum australe, R. Br. 

 I reported the discovery as a new record for Western Australia 

 at a meeting of the W. A. Natural History Society held 26th 

 November, 1907. Shortly after this doubts were thrown upon 

 my determination, and owing to unavoidable delays the matter 

 has only just been cleared up. I have recently received from 

 Dr. R. S. Rogers, of Adelaide, many dried and fresh specimens 

 of undoubted P. australe, collected at Mount Compass, South 

 Australia. After carefully comparing my Western specimens 

 with these I am satisfied that there is no essential difference. 

 My specimens are larger, more robust, and more richly coloured 

 — all differences that may be due to habitat. 



This Westralian form of Prasophyllum australe has a truly 

 beautiful inflorescence, in this respect being perhaps unique 

 in the genus. Closely examined, the individual blossom yields 

 to that of P. datum, R. Br. ; but the half-open scape would be 

 difficult to excel for effectiveness of colour scheme. The stem 

 and leaf, together with the bracts, dorsal sepal, and petals are 

 deep purphsh-green, or " black," as it is often called ; the 

 lateral sepals and labellum are pure white, while shaded splashes 

 of pink on callus and column tone and give piquancy to the 

 vivid contrast of the other parts. There is a small detail I 

 would add to the description of the species given in " Flora 

 Australiensis " : the anther connective is produced into a fine 

 pungent mucro. This seems better developed in the Western 

 form. 



While morphologically my plant is so Hke its Eastern con- 

 geners, ecologically there are some remarkable differences. 

 Dr. Rogers states that in South Austraha P. australe grows in 

 swampy or wet ground {Trans. Royal Soc. of S.A., vol. xxxiii.. 



