Addisonia 19 



(Plate 234) 



POLYSTACHYA MINUTA 

 Polystachya 



Native of Florida, the West Indies, and South America 

 Family Orchidaceas Orchid Family 



Epidendrum minutum Aubl. PI. Guian. 2: 824. 1775. 



Dendrobium polystachyum Sw. Sv. Vet.-Akad. Nya Handl. 21: 247. 1800. 



Cranichis luteola Sw. Fl. Ind. Occ. 1433. 1806. 



Polystachya luteola Hook. Exot. Fl. pi. 103. 1825. 



Polystachya minuta Britton; Small, Fl. SE. U. S. 328, 1329. 1903. 



This is one of the most abundant and widely distributed orchids 

 of tropical America, usually growing on trees in moist or wet 

 situations, but like some other epiphytic plants it is sometimes seen 

 on rocks or cliffs, indicating that the epiphytic habit is a mechanical 

 rather than a biological one; its cord-like roots clasp the tree or 

 rock rather firmly. It is a member of a very large genus, some one 

 hundred and seventy species having been recognized by botanists, 

 natives of tropical regions of both the Old World and the New. 

 P. minuta is the only one of them which reaches the continental 

 United States, in Florida, where it has been found as far north as 

 Miami. It is the type species of the genus, and was first described 

 from plants collected in French Guiana prior to 1775. 



The accompanying illustration was made from a plant collected 

 by Mrs. N. L. Britton and Miss Delia W. Marble in February 1913, 

 at St. Peter, St. Thomas, Virgin Islands, which subsequently 

 flowered at the New York Botanical Garden. 



Polystachya minuta is not a showy orchid, its flowers, while often 

 numerous, being small. It has rather slender stiff stems up to 

 about two feet in length, with several striate leaf-bearing sheaths 

 an inch or two long, and terminated by one or several racemes of 

 greenish-yellow flowers one quarter to one third of an inch broad; 

 the leaves are borne mostly below the middle of the stem, are 

 oblong or linear-oblong, blunt or pointed, from two inches to about 

 a foot long, and about an inch broad or less, and they are con- 

 duplicate when unfolding; the flower-buds are obliquely three- 

 angled; the middle sepal is ovate, the two lateral ones oblique; the 

 petals are narrowly spatulate and a little shorter than the sepals; 

 the lip is glandular-hairy on the inner side, three-lobed, the middle 

 lobe notched, the lateral lobes incurved; the anthers contain four 

 waxy pollinia; the fruit is an oblong capsule five or six lines long. 



N. L. Britton. 



Explanation of Plate. Fig. 1. — Summit of stem, with upper leaves and 

 inflorescence. Fig. 2. — Base of stem, with leaf. Fig. 3. — Flower, X 3. Fig. 4. 

 — Flower, the sepals removed, X 3. 



