ORCHIDACE.E 



Isotria verticillata, like Pogonia ophioglossoides, propagates by- 

 means of root-shoots. It has a vertical rhizome covered with fus- 

 cous pubescence. The root-shoots, in this species, may attain an 

 extraordinary length. (Cf. Plate 106.) The secondary stems are 

 tubular with a few basal bracts and are terminated by a verticil 

 of from five to six leaves, which at the time of anthesis are very 

 slightly developed and only attain full size when the flowering 

 season is drawing to a close. In the verticil two leaves are super- 

 posed. In seedlings (cf. Plate 106) of this species the earher 

 stages are characterized by two, three or four leaves, and it would 

 appear that vegetative maturity is not attained in the first two 

 or three years of growth. 



The attitude of the flower is characterized by several positions. 

 At first the sepals, petals and lip point toward the zenith. This 

 attitude owes its occurrence to the peculiar type of leaf verna- 

 tion already mentioned. At this stage the upper sepal is bent 

 sharply backward and the leaves are comparatively small, almost 

 bract-like, but as the flower matures and the sepals and petals 

 point toward the horizon, they develop rapidly and in a sur- 

 prisingly brief time increase to their normal size. In a few days 

 the flowers begin to droop, and if pollination has been effected 

 and fertilization secured, the perianth falls away and the capsule 

 assumes a vertical position; if pollination has not resulted in fer- 

 tilization, the perianth together with the pedicel and ovary drops 

 to the ground. 



Germination of the pollen before transference to the stigma 

 has been observed in this species, but that self-fertilization is 

 effected by pollen tubes reaching the stigma while the grains are 

 still in situ has not been demonstrated. In Plate 105 a germi- 

 nating tetrad is shown. 



Isotria verticillata is a woodland species and is often associated 



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