Platanthera. ORCHIDACE^. 279 



angular. Leaves 3-8 inches long and from half an inch to an inch and a half wide, mostly 

 acute, but sometimes obtuse. Flowers pale greenish yellow, middle sized. Upper sepal 

 obtuse ; the lateral ones oblique or twisted, and rather acute. Petals often a little retuse, 

 longer than ihe sepals. Lip more than twice as long as the sepals ; the middle segment with 

 a long slender base, and, as well as the others, cut into a few capillary segments. Spur con- 

 siderably thickened towards the extremity, rather acute. 



Moist meadows and thickets ; frequent. Fl. June - July. An unobtrusive species, often 

 overlooked among other tall herbs. 



10. Platanthera bracteata. Green-jlowered Orchis. 



Stem leafy ; spike loose, the bracts leafy, 2-3 times longer than the flowers ; petals 

 linear-lanceolate, erect ; lip oblong-linear, slightly bifid at the apex, with a minute central 

 tooth ; spur very short, obtuse and somewhat inflated. — Orchis bracteata, Willi, sp. 4. p. 34 ; 

 Pursh, Jl. 2. p. 587 ; Bigel. fl. Bost. p. 320. Satyrium bracleatum, Pers. syn. 2. p. 507 ; 

 Muhl. cat. p. 80. Habenaria bracteata, R. Br. in hort. Kcw. (ed. 2.) 5. p. 192 ; Torr, 

 compend. p. 318 ; Beck, hot. p. 348 ; Darlingt. fl. Cest. p. 507. Peristylis bracteatus, 

 Lindl. Orchid, p. 298 ; Hook. fl. Bor.-Am. 2. p. 201. 



Root fasciculate or tuberous. Stem 6-12 inches high. Leaves 3-4 inches long, broadly 

 lanceolate, acute, or the lowest one sometimes obtuse. Spike few-flowered, 2-3 inches long ; 

 the flowers small, greenish. Bracts linear-lanceolate, spreading and conspicuous. Sepals ovate, 

 erect. Petals rather shorter than the sepals. Lip sometimes spalulate, truncate at the tip, 

 and furnished with 3 teeth, of which the middle one is very small, or sometimes almost 

 wanting. Spur less than half the length of the lip, somewhat 2-lobed, saccate and trans- 

 lucent. 



Shady woods : rare. End of May - June. 1 have not adopted the genus Peristylis, 

 because it seems to-difi'er from Platanthera in scarcely any thing except the short spur. 

 Our plant is so nearly related to Peristylis viridis of Lindley (Satyrium viride, Linn.), 

 that Lindley and Sir William Hooker think it is hardly distinct. 



Tribe IV. ARETHUSEjE. Lindl. 



Anther opercular, terminal. Pollen-masses farinaceous, or consisting of loosely cohering 



grains. 



9. ARETHUSA. Gronov. ; Lindl. Orchid, p. 426. arethusa. 



[So named from Arethusa, a nymph of Diana.] 



Flower somewhat ringent. Sepals and petals somewhat equal, connivent and cucullate 

 above, cohering at the base. Lip deflected at the apex, bearded inside. Pollen-masses 4, 

 angular. — A small plant with a bulbous root, and single large terminal flower ; the leaf 

 nearly concealed in the sheathing scales of the scape. 



