470 



BOTANY. 



Tribe II. Neottiece, with a single dorsal anther, containing 

 two or four soft pollen masses attached to a viscid disc. Our principal 

 genus is Spiranthes. 



Tribe III. Aretftusece, with a single terminal anther, contain- 

 ing two or four powdery pollen masses. 



Our native Arethv&a and Cal->pOffon are fine representatives of this 

 tribe. The Vanilla plant (Vanilla plauifolia, and other species) of 

 tropical America, a climbing epiphyte, produces fleshy capsules 12 to 

 25 cm. (510 in.) long, which are highly aromatic, and much used in 

 the manufacture of confections, beverages, medicines, etc. When first 

 introduced into the East Indies, where it is now much grown, it failed to 

 perfect fruit ; artificial p llination hav- 

 ing been resorted to, however, the dif- 

 culty at once disappeared. (Fig. 363.) 

 Tribe IV. Ophrydece, with a 

 single anterior anther, containing two 

 stalked pollen masses, each attached to 

 a viscid disc (Fig. 361). 



Our pretty little Orchis spectabilis, 

 and many species of Hdbenana, are 

 our principal representatives of this 

 tribe. From the tubers of Orchis mas- 

 cula and other European and Asiatic 

 species, the starchy-mucilaginous and 

 highly nutritious substance " Salep," 

 is obtained. 



Tribe V. Vandece, with a single 

 terminal or dorsal anther, containing 

 Fig. 362 Sexual organs of the waxy pollen masses attached to a vis- 

 flower of Ct,pri]>e(iium calceolus, the c jd disc 

 perianth, p, removed. A, side view. 

 B, back view. C, front view. /, the We have no native representatives 



imstenTium*-^ a^taiii^""^"^^^ * *^ 8 tr i e - Many of the tropical 

 stamen or etaniinode ; ,' stigma. species are of wonderful forms; indeed, 

 After Sachs. ag Mr D arw m says of them, tlu-y arr 



" the most remarkable of all Orchids." In some genera they assume 

 the most curious forms, resembling insects of various kinds, birds, etc., 

 etc. In Catasetum saccatum, a diclinous South American species, 

 when certain sensitive parts of the column of the male flower are 

 touched by an insect, the pollen masses are by a peculiar contrivance 

 thrown out forcibly in such a direction as to strike the insect, to 

 which it adheres by a viscid disc, and is thus carried to and brought in 

 contact with the stigma of the female flower. 



Tribe VI. Epidt ii(/rea>, with a single terminal anther, contain- 

 ing stalked, waxy pollen masses, these not attached to a viscid disc. To 

 this tribe belong in the United States Tipularia, Bletia, ami l^ii'lm- 

 drum, the latter an epiphyte, occurring only in the Southern States. 



