THE TASMANIAN FLORA. 



185 



■2. ELODEA. 



Staminate flowers minute, sessile in the leaf axils. Pistillate flowers 

 solitary, axillary, on a slender stalk, continuous above into the filiform 

 ovary. 



A small American genus. 



W. CANADENSIS, Ricli. Submerged, spreading, and much-branched. Leaves 

 oblong, about j inch long, numerous, spreading, opposite or whorled. 

 Perianth of female flower about 1^ line diameter, on a slender stalk 

 I -3 inches long. Anacharis alsinastrum, L. 



Common about Hobart, Jordan, &c. Introduced, and apparently 

 only the female plant. PI. Dec-Mar. 



Oeder hXXY —0RCI£IDACE^. 



Perianth superior, usually irregalar. Segments 6, in 2 series. Of the outer 

 three, or sepals, the one in the median plane is termed the dorsal sepal, the other 

 two are the lateral sepals. Of the inner series, petals, one is usually much 

 modified in shape, and is called the labellum. Stamens combined with the style 

 in a column, the stigma developing close below the anthers. Between the two 

 organs is developed a process, the rostellum. Pollen in masses, attached to a 

 sucker-like deciduous club, derived from the rostellum. Ovary 1-celled, with 3 

 parietal placentas. Ovules numerous. 



A large order, of world-wide distribution. 



Leaves on the scape more than one. 

 Leaves very distinct from bracts. 



Leaves cylindrical, nearly woody ... ... 1. Dendrohium,. 



Leaves flat. 



Flowers white, spotted with pink, in a drooping 

 panicle... ... ... ... ... ... 2. 



Flowers green or purple-brown. 



Flow:ers green, hood-shaped... ... ... 14. 



Flowers green or purple-brown. The 



labellum with conspicuous glands ... 22. 



Flowers purple-brown. The labellum long 

 and broad ... ... ... ... ... 10. 



Leaves passing gradually into bracts. 



Flowers numerous, small, pink, in a spiral round 



the stem ... . . ... ... ... ... 5. Spiranthes. 



Flowers with a long labellum covered with long 

 purple and brown hairs ... ... ... 6. 



Flowers green, hood-shaped ... ... .-14. 



Flowers slate-coloured, merging into green, 



yellow, or purple-brown. The Upper segment 



nearly hood-shaped, the 2 lowest very long 



and linear .-■ ... ••■ •■• ... 9. 



Flowers nearly regular, blue, pink, white, or 



yellow 

 Flowers very irregular, yellow, often blotched 

 with purple-brown 

 Leaves on the scape solitary, flat, broad. 

 Leaves heart-shaped or nearly so. 



Flower solitary, broadly hood-shaped, close to 

 to the leaf ... ' 13. Corymiithes. 



1. 



Sarcochilus. 

 Pterostylis. 

 Chiloghttis. 

 Cryptostylis. 



CalocMlus. 

 Pterostylis. 



Orthoceras. 



Thelymitra. 



Diuris, 



