386 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1917. 



ORCHIDS. 



Most of the orchids of Paradise Key are modest and inconspicuous 

 when compared with their gorgeous relatives in our conservatories; 

 but some of them are prized for their odd forms or their fra- 

 grance, and all of them are attractive both to botanists and to lay- 

 men. Some of the most interesting are shown on plate 19. Spathiger 

 rigidus (fig. 1)), a creeping epiphyte widely spread in the West 

 Indies, with pale, yellowish-green flowers, blooms continuously 

 throughout the greater part of the year. The spicier orchid, AuUza 

 nocturna (fig. 2), also "West Indian in its distribution, takes its spe- 

 cific name from the exquisite fragrance which its large, white, nar- 

 row-petaled flowers exhale toward nightfall. The shell orchid, 

 Anachettivm cocbleatwm (fig. 3), was first designated by old Hans 

 Sloane in 1707, as a "mistletoe with a bulbous root and a showy, 

 larkspurlike flower." The chintz-flowered orchid, Oncidium imdu- 

 latum (fig. 4), has odd-looking, mottled flowers, also described by 

 Sloane, who likened them to patches of Dutch chintz. Macra- 

 denia lutescens (fig. 5) is a modest, little plant with drooping flowers 

 dotted with purplish brown. The marsh orchid, Oncidium, spliace- 

 lotitm (fig. 6), usually found growing on the edges of swamps, has 

 conspicuous, yellow flowers spotted with Avine color. 



OTHER EPirHYTES. 



In addition to the epiphytal orchids other plants are found grow- 

 ing on the limbs and trunks of forest trees, among them the resur- 

 rection fern, which curls up during periods of drought and uncurls 

 its fronds when moisture returns; a fleslry leaved Peperomia which 

 creeps along the tree trunks; the well-known Dendropogon, or 

 Spanish moss, which hangs in festoons from the branches (pi. 20) ; 

 and its relatives of the pineapple family, the stiff-leaved bromeliads 

 (pi. 21). It is interesting to note in connection with the latter 

 that the bases of the leaves of man}' bromeliads collect water in which 

 insects lay their eggs and undergo their transformations. In some 

 parts of tropical America, in regions remote from water, certain 

 dragon flies and even frogs habitually lay their eggs in such reser- 

 voirs, which have been collectively called an epiphytal swamp re- 

 gion, which has the important advantage over a true swamp that 

 it never dries up. 



In addition to the marsh ferns and the epiphytal resurrection fern 

 already mentioned there are several other interesting species, includ- 

 ing a delicate, little, filmy fern (fig. 10) growing among moss on 

 the trunks and limbs of trees; the epiphytal grass fern, Vittaria 

 lineata, and golden Phlebodium, with large fronds lobed like an 

 oak leaf and dotted beneath with conspicuous sori (pi. 22), often 



