88 OECHIDACEAE. 



decaying: perianth green and white: lateral sepals lanceolate, 4-4.5 mm. long: 

 petals linear : lip oblong, 4-4.5 mm. long, the callosities directed sideways. — 

 Common, on roadsides, banks, and open hillsides. — Sum. 



3. I. vemale (Engelm. & Gray) House. Stem 1.5-5.5 dm. tall: blades of the 

 lower cauline leaves elongate, linear, sometimes broadly so, 7-15 cm^ long : peri- 

 anth mostly yellowish: lateral sepals lanceolate, 6-10 mm. long: petals linear 

 or linear-oblong: lip ovate, 6-8 mm. long, the callosities incurved. — Occasional, 

 in sandy or gravelly soil. — Sum. and fall. 



4. I. praecox (Walt.) House. Stem 2-8 dm. tall: blades of the lower cauline 

 leaves elongate, linear or nearly so, 5-30 cm. long: perianth white: lateral 

 sepals lanceolate or linear-lanceolate, 5-7 mm. long: petals linear: lip oblong, 

 5-7 mm. long, the callosities straight. — S. Occasional, in wet grassy meadows. 

 — Schists. — Sum. 



5. I. cernuum (L.) House. Stem 2-7 dm. tall: blades of the lower cauline 

 leaves linear to narrowly oblong, oblong-lanceolate or sometimes linear-oblanceo- 

 late, 8-30 cm. long: perianth white or yellowish: lateral sepals lanceolate, 9-10 

 mm. long: lip ovate or oblong-ovate, mostly 8-11 mm. long, the callosities 

 incurved. — Common, in wet places and damp thickets. — Sum. and fall. 



6. I. plantagineum (Eaf.) House. Stem 1-4 dm. tall: blades of the lower 

 cauline leaves broadly linear to oblong, 5-15 cm. long: perianth mainly white: 

 lateral sepals narrowly lanceolate, 5-6 mm. long: petals linear, about as long, 

 as the sepals: lip quadrate-oblong, 5-5.5 mm. long, the slender callosities 

 rather spreading. — M. S. Rare, in meadows and along streams. — Limestones, 

 schists. — Spr. and sum. 



14. PERAMIUM Salisb. Caulescent herbs with scape-like stems. Leavea 

 various, those near the base of the stem with dilated blades, those higher up 

 mere sheathing scales. Flowers in a spike. Perianth very inequilateral. Lip 

 sessile, sac-like, with a small blade and a large saccate base. 



1. P. pubescens (Willd.) MacM. Plant 1.5-5 dm. tall: blades of the lower 

 cauline leaves oblong, elliptic, or ovate, 2-5 cm. long: lateral sepals about 5 

 mm. long: petals about as long as the sepals, obtuse: lip 4 mm. long, the edge 

 undulate. — Occasional, in woods. — Sum. — Eattlesnake-plantain. 



15. MAIjAXIS L. Scapose herbs with corms. Leaves mainly elongate 

 sheaths, the upper one bearing a dilated blade at the top. Flowers in a term- 

 inal raceme. Perianth white or greenish. Lateral sepals slightly inequilateral. 

 Petals linear-filiform or filiform, shorter than the sepals. Lip broad, cordate 

 at the base, sometimes lobed at the apex. 



1. M. imifolia Michx. Leaves mostly solitary; blades oblong, ovate, or oval, 

 2-6 cm. long : scape 1-3 dm. tall : raceme stout : lateral sepals ovate or oblong- 

 ovate, 1-1.5 mm. long, obtuse: lip about 2.5 mm. long, the 2 lateral lobes much 

 longer than the middle one : capsule 5-6 mm. long. — S. Not very common, in 

 rich woods. — Schists. — Sum. — Adder 's-mouth. 



16. LIPABIS L. C. Eich. Scapose green herbs with corms. Leaves 2 or 

 more at the base of the scape with wide blades, accompanied by several scales. 

 Flowers in a terminal raceme. Perianth greenish. Lateral sepals narrow, 

 nearly equilateral. Petals elongate-linear or filiform, longer than the sepals. 

 Lip free, dilated, undulate or erose, sometimes with tubercles at the base. — 



Spr. — TWAYBLADE. 



Lip with an undulate blade 2.5-3.5 mm. wide : petals narrowly linear. 



1. L. Loeselii. 

 Lip with an erose blade 12-13 mm. wide : petals linear-filiform. 2. L. liliifoUa. 



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