16. Orthoceras. ORCHID ACEAE. 145 



without a definite point, rather higher than the viscid disk of the rostellum. Lateral 

 appendages of the column subulate or linear-falcate, about same height as the viscid disk. 

 Longwood and Mount Lofty Range ; Myponga ; Mount Compass ; Port Elliot ; 

 Kangaroo Island. Nov. -Dec. 



8. D. SUlphurea (sulphur-colored), R. Br. A stouter and larger plant than the preceding, 

 often 50 cm. high. Leaves 2 or rarely 3, much exceeding the middle of the stem, 18-45cm. 

 long, lax, linear, never setaceous. Flowers large, often upwards of 5 cm. in the long 

 diameter, yellow with dark brown markings closely resembling those of D. brevifolia 

 but with an additional transverse marking across the tip of the labellum ; 3-6, on long 

 slender pedicels. Dorsal sepal ovate, recurved, about 20 mm. long ; lateral sepals linear, 

 acuminate, about 22 mm. long, spreading, usually parallel, but sometimes crossed. Petals 

 spreading 20-21 mm. long ; stalk 5-6 mm. long ; lamina elliptical about 15mm. long. 

 Labellum sessile, much shorter than dorsal sepal, about 12 mm. long ; lateral lobes 

 rather wide and blunt, obovate, hardly half as long as the middle lobe ; middle lobe 

 rhombo-cuneate, wide but depressed on each side of the central line ; lamina with a 

 single conspicuous raised longitudinal line from the base to a little beyond the middle, 

 where it merges into the natural central keel or fold of the lobe. Anther hardly pointed, 

 its apex as high as the viscid disk of the rostellum. Lateral appendages of column slightly 

 exceeding this, semiovate, incurved. 



Mount Gambier district ; also in all the eastern States and Tasmania. Nov. 



16. ORTHOCERAS, R. Br. 



(Greek orihos, straight ; keras, horn.) 



Dorsal sepal rather broad, incurved, contracted at the base, hood-shaped ; lateral 

 sepals much longer, narrow-linear, spreading laterally. Petals short, erect, often 

 oblong or cuneate. Labellum recurved, 3-lobed ; the middle lobe contracted at the base 

 and much longer than the lateral ones ; a large fleshy callus at the base. Anther erect 

 or incurved, tapering to the apex, 2 -celled, on an extremely short filament arising from 

 the posterior border of the floral receptacle ; the lateral appendages or wings of the 

 filament erect or incurved and adnate to the base (the style) of the stigmatic -plate as in 

 some members of the genus Prasophyllum. The stigmatic -plate, carrying the stigma 

 and rostellum, erect in front of the anther. Pollen-masses 2, each bilobed, cohering 

 near their apices ; suspended loosely from the anther-septum after dehiscence, but later 

 dropping on to the back of the stigmatic -plate without any sort of attachment to the 

 rostellum ; mealy and friable. The viscid disk of the rostellum and caudicle absent. — 

 Terrestrial glabrous herbs, with more or less ovoid tubers ; 2 or 3 membranous scales 

 at the base of the scape. Leaves radical or almost so, several, linear. Flowers on short 

 pedicels, rather distant and racemose. 



The genus contains but one species which is found also in New Zealand. 



1. 0. strictum yupright), R. Br. (Text fig. 34, B.) A rigid species with the characters 

 of the genus, 15-45 cm. high, Leaves 2-5, acute, channelled, sheathing at the base. 

 Stem-bracts 1, sometimes 2, at or about the middle, with long sheathing base and subulate 

 lamina. Flowers greenish-brown or quite green, 2-7 on rather short pedicels. Dorsal 

 sepal with an acute apex, about 11 mm. long ; lateral sepals almost terete, at maturity 

 laterally spreading on each side of the hood, about 2.7 cm. long. Petals hidden by the 

 dorsal sepal, about 5 mm. long, tips rather blunt and usually notched. Labellum sessile, 

 about 10 mm. long and 7 mm. wide ; the lateral lobes broad, erect, not more than half 

 the total length, margins entire ; middle lobe somewhat elliptical w ith entire margins ; 

 lamina smooth except for a large pyramidal callus at the base. Column about 4 mm. 

 long. Anther without a point, much incurved. Lateral appendages of column variable 

 in length but usually same height as rostellum. 



N. P. and Mount Lofty Range ; Golden Grove ; Goolwa ; Millicent district ; also all 

 Eastern States, Tasmania, and New Zealand. Nov. -Dec. 



17. SPIRANTHES, Richard. 

 (Greek speira, a coil ; anthos, a flower.) 

 Perianth -segments subequal. Dorsal sepal erect or incurved over the column, ovate, 

 concave ; lateral sepals free, ovate -lanceolate, erect or spreading. Petals truncate, erect, 

 their posterior margins concealed by the dorsal sepal and forming with that segment a 

 hood. Labellum about as long as the sepals, on a very short claw, undivided ; the lower 

 half erect with entire margins embracing the column ; the tip recurved ; the lamina with 

 2 rounded glandular bodies at the base. Column erect, very short, contracted in the lower 

 half, clinandrium expanded. Anther blunt or very minutely apiculate, incumbent against 

 the back of the stigma, valvate, 2-celled. Column-wings membranous, stretching between 

 the anther-filament and the stigmatic -plate, adnate to the pedicel (style) of the latter 

 and also to the margins of the stigma itself, forming a pouch between the male and female 

 elements. Stigmatic surface large, about the same length as the rostellum. Rostellum 

 forming with the viscid disk a long membranous structure much exceeding the anther 



