464 ORCHIDE^E 



strongly ribbed leaves; and a long raceme of yellowish-green 

 fiowers with a 2-lobed lip. — Woods and orchards ; common. — Fl. 

 May — July. Perennial. 



6. Spiranthes (Lady's Tresses). — Root tuberous; stem leafy; 

 flo7vers in a spirally-twisted spike ; lip not spurred, united to the 



lIstera ovata (Twayblade). 



base of the column ; pollen powdery. (Name from the Greek 

 speira, a spiral, anthos, a flower.) 



1. S. autumndlis (Autumn Lady's Tresses). — Root of 2 or 3 

 ovoid tubers ; stem 4 — 8 in. high, slender, slightly pubescent ; 

 radical leaves ovate, acute ; flowers in a close spiral, white, 

 fragrant in the evening. — Dry downs ; not uncommon. The 

 flowers are arranged in a single row and the spiral turns either 

 from left to right or from right to left. The leaves form a tuft 



