155 



longitudinally veined. Sepals similar, acute, oblong-elliptical, 

 about 16 mm. long and 5 mm. wide. Petals obovate, about 

 18 mm. long and 10 mm. wide. Spur 2-fid; the lower seg- 

 ment oblong-cylindrical, very obtuse, about 3 mm. long. 

 Labellum about 13 mm. long and 10 mm. wide (flattened out) ; 

 3 -fid; middle lobe obtusely oblong; lateral lobes wide and 

 rounded ; lamina with rather numerous calli distributed along 

 the nerves, but chiefly in about 6 rows terminating near the 

 centre, longitudinally veined. Northern Australia: Groote 

 Eylandt, Gulf of Carpentaria; Mr. N. B. Tindale. August, 

 1921. 



Spiranthes australis, Lindl. Column erect, about 

 3 mm. long, fleshy, contracted in its lower half, clinandrium 

 dilated; anther valvate, 2-celled, blunt or minutely apiculate, 

 inclined against the back of the stigma and reaching to about 

 its upper border; the wings represented by a membrane on 

 each side stretching between the "filament" of the anther and 

 the stigmatic-plat-e,(i) adnate to the pedicel (''style") of the 

 latter and also to the lateral margins of the stigma itself, 

 forming a pouch between the male and female elem.ents of 

 the column, the bases of the pollinia released quite early 

 from the anther so as to rest in the bottom of this pouch. 

 Stigmatic surface U-shaped, large and slightly sloping down- 

 wards. The rostellum (including the disk) almost equal in 

 length to the stigmatic surface, arising from the upper border 

 of the latter, forming a long narrow membranous structure 

 much exceeding the anther in height; with a short rigid 

 acut« bifid base persisting after the membranous portion has 

 been removed, or as a long split membranous structure after 

 removal of the disk and pollinia only. The disk slate 

 coloured, long narrow elliptical (or "boat-shaped") accom- 

 modated in a fork of the rostellum and covered by a mem- 

 branous capsule derived from the latter and containing a 

 viscid fluid; the capsule attached to the lateral margins of 

 the disk and traversed by a central vertical furrow. Pollinia 

 lamellated, in 2 pairs, the latter club-shaped or pyriform, 

 granular ; the apices of the pairs lightly united, exposed above 

 the anther-case and attached by a short caudicle to the 

 back of the disk; capsule of disk easily ruptured artificially 

 so as to permit removal of the pollinarium. 



Tlie structure of the column in Spiranthes australis is 

 comparable to that in the genus Prasophyllum, but in the 

 former the wings of the anther-filament are adnate not only 

 to the pedicel of the stigmatic-plate, but also to the margins 

 of the stiofma itself. 



(1^ Rogers, Titans. Roy. Soc. S. Austr., xlv. (1921), p. 264. 

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