BURMANNIACEAE. 



i. Burmannia biflora L,. Northern 

 Burmannia. (Fig. 1087.) 



Burmannia biflora L. Sp. PI. 287. 1753. 

 Tripterella coernlea Nutt. Gen. i: 22. 1818. 



Stems very slender, 2 / -6 / high, from a few 

 fibrous roots, simple or forked above. Flowers 

 i or several, often 2, terminal. Angles of the 

 perianth-tube conspicuously winged, the outer 

 lobes ovate, acute, the inner linear and in- 

 curved; seeds very numerous, oblong-linear, 

 sparingly striate, escaping through irregular 

 fissures in the sides of the capsule. 



In swamps and bogs, Virginia to Florida and 

 Louisiana. Sept. -Nov. 



Family 28. ORCHID ACEAE Lindl. Nat. Syst. Ed. 2, 336. 1836.* 



ORCHID FAMILY. 



Perennial herbs, with corms, bulbs or tuberous roots, sheathing entire leaves, 

 sometimes reduced to scales, the flowers perfect, irregular, bracted, solitary, 

 spiked or racemed. Perianth superior, of 6 segments, the 3 outer (sepals) sim- 

 ilar or nearly so, 2 of the inner ones (petals) lateral, alike; the third inner one 

 (lip) dissimilar, often markedly so, usually larger, often spurred, sometimes in- 

 ferior by torsion of the ovary or pedicel. Stamens variously united with the 

 style into an unsymmetrical column; anther i or in Cypripedium 2, 2 -celled; pol- 

 len in 2-8 pear-shaped usually stalked masses (pollinia), united by elastic threads, 

 the masses waxy or powdery, attached at the base to a viscid disk (gland). 

 Style often terminating in a beak (rostellum) at the base of the anther or be- 

 tween its sacs. Stigma a viscid surface, facing the lip beneath the rostellum, 

 or in a cavity between the anther-sacs (cliiiandrium). Ovary inferior, usually 

 long and twisted, 3-angled, i -celled; ovules numerous, anatropous, on 3 parie- 

 tal placentae. Capsule 3-valved. Seeds very numerous, minute, mostly spindle 

 shaped, the loose coat hyaline, reticulated; endosperm none; embryo fleshy. 



About 410 genera and 5000 species, of wide distribution, most abundant in the tropics, many of 

 those of warm regions epiphytes. 



Anthers 2; lip a large inflated sac. i. Cypripedinm. 



Anthers solitary. 



Anther-sacs divergent; pollinia with a caudicle which is attached at base to a viscid disk or gland. 

 Glands enclosed in a pouch. 2. Orchis. 



Glands not enclosed in a pouch. 3. Habenaria. 



Anther-sacs parallel; pollinia not produced into a caudicle (except apparently in no. 14). 

 Pollinia granulose or powdery. 



Flowers solitary or few; anther incumbent on a column 4" long or less. 

 Lip crested with straight, somewhat fleshy hairs. 



Column clavate ; lip free. 4. Pogonia. 



Column linear, dilated above, the lip adherent to its base. 5. Arelhtisa. 

 Lip bearded with long club-shaped hairs. 15. Limodorum. 



Flowers numerous, in spikes or racemes; anther erect, jointed to a column not over 2" 



long. 



Anther operculate ; leaves broad, alternate. 6. Epipactis,. 



Anther not operculate. 



Leaves green, borne on the stem. 



Leaves alternate; spike mostly twisted. 7. Gyrost achys. 



Leaves 2, opposite; spike not twisted. 8. Listera. 



Leaves white-reticulated, basal. 9. Periamium. 



Pollinia smooth and waxy. 



Plants with corms or solid bulbs; leaves basal or cauline. 

 Leaves unfolding before or with the flowers. 



Leaf cauline; lip ovate, or auricled at the base. 10. Achroanthes. 



Leaf or leaves basal. 



Leaves 2; lip flat; flowers racemed. 

 Leaf i; lip saccate; flower solitary. 





11. Leplorchit. 



12. Calyftso. 



*Text contributed by the late Rev. THOMAS MORONG. 



