XVIII. Orchidaceae. Orchis Family

Perennial herbs, often with corms or tuberoid roots, sometimes rootless saprophytes; leaves paralleled-nerved, solitary or several, alternate; flowers solitary, in racemes or spikes, perfect, zygo-morphic, gynandrous with the perianth adnate to the one-celled ovary, one division termed the lip differing from the rest in shape, and sometimes prolonged into a spur at the base; fruit a one-celled, three-valved capsule.

Tribe Cypripedieae

I. Cypripedium. L.

1. C. pubescens. (Willd.) Knight. Large Yellow Lady's Slipper.

2. C. parviflorum. Salisb. Small Yellow Lady's Slipper.

3. C. passerinum. Richards. White Moccasin Flower.

Tribe Ophrydieae

II. Orchis. (Tourn.) L.

1. O. rotundifolia. Banks. Fly-spotted Orchis. III. Habenaria. Willd.

1. H. dilatata. (Pursh.) Gray. White Rein Orchis.

2. H. bracteata. (Willd.) R. Br. Long-bracted Rein Orchis.

3. H. obtusata. (Pursh.) Richards. Northern Rein Orchis.

4. H. hyperborea. (L.) R. Br. Leafy Rein Orchis.

5. H. gracilis. Wats. Graceful Rein Orchis.

6. H. orbiculata. (Pursh.) Torr. Round-leaved Rein Orchis.

Tribe Neottieae

IV. Spiranthes. Richards.

1. S. Romanzoffiana. Cham. Hooded Ladies' Tresses. V. Epipactis. (Haller.) Boehm.

1. E. decipiens. (Hook.) Ames. Stout Rattlesnake Plantain. 2. E. repens. (L.) Crantz. Small Rattlesnake Plantain. VI. Listera. R. Br.

1. L. cordata. (L.) R. Br. Heart-leaved Twayblade. 2. L. convallarioides. (Sw.) Torr. Broad-lipped Twayblade.

Tribe Epidendreae #

VII. Corallorhiza. (Haller.) R. Br.

1. C. trifida. Chatelain. Early Coral Root.

2. C. maculata. Raf. Spotted Coral Root.

3. C. striata. Lindl. Striped Coral Root.

4. C. Mertensiana. Bong. Spurred Coral Root. VIII. Calypso. Salisb.

1. C. bulbosa. (L.) Oakes. Calypso.