ORCHID FAMILY. Orchidaceae. 



Heart-leaved A delicate plant with a very slender 

 Twayblade stem bearing two opposite light green, 

 Listera cordata stemless leaves shaped somewhat like the 

 Madder purple ace o y spades, and a loose cluster about 2 



inches long of tiny dull purple flowers. 

 The flower is without a spur but possesses a very long 

 two-cleft lip, bearing nectar in a furrow ; the slightest 

 disturbance of a visiting insect causes the delicate ros- 

 tellum above the lip to explode and forcibly eject a 

 sticky fluid which is sure to hit the pointed tops of the 

 pollen-masses lying just over the crest of the rostellum. 

 Thus, the insect coming in contact with the sticky fluid 

 withdraws fluid and pollen-masses. Smaller members 

 of the family Hymenoptera, the bees, etc., most fre- 

 quently visit the flower, also those of the order Diptera, 

 flies, notably the tiny beelike ones. 3-10 inches high. 

 Named for Martin Lister an early English botanist. 

 Moist woods, Me. to N. J., and west to Ore. Found in 

 the woods about Mt. Washington. 



Broad-lipped A similar species with leaves less heart- 

 Tway blade shaped and flowers with a wedge-oblong 

 Listera conval- jj pj muc h longer than the narrow sepals 

 Greenish an( ^ P 6 ^ 8 - Sepals purplish. In damp 



yellow woods. Me., south to N. Car., in the 



June-July mountains, and west to Minn. 

 Ladies' Tresses A marsh orchid, with a peculiarly twisted 

 Spiranthes or spiral flower-spike and very light green 



linear leaves not nearly as tall as the 

 white*' 8 flower-stem. The flowers translucent yel- 



August- lowish white, or variably cream white, 



September odorless or fragrant, the whiter ones gen- 

 erally most fragrant, the lower sepals not upturned or 

 joining with the upper, the latter arching and joined to 

 the petals; all these parts with the curly -edged broader 

 lip forming the bugle-horn-shaped tiny flower. It is 

 fertilized by some of the smaller bees, moths, and but- 

 terflies. In Spiranthes the rostellum holds in its centre 

 a narrow boat-shaped disc containing a sticky fluid ; it 

 is covered by a membrane easily ruptured by an insect. 

 After the rupture the exposed sticky fluid glues itself to 

 the tongue of the insect and the boatlike disc is with- 

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