Auricled Twayblade 



The auricled twayblade, another threatened orchid, is a diminutive herbaceous 

 monocot that usually inhabits alder thickets. It is found from northern New 

 England to northern Michigan, and northward to the Canadian subarctic. The 

 only collections of this plant in coastal Maine were made on Mt. Desert 

 Island (region 5) in 1891 and 1927. Its current status is unknown. It has 

 been collected at 18 locations in Maine outside the coastal zone, but not in 

 recent years. 



Little biological information is available on this species. Other species of 

 this genus reproduce both sexually (seeds) and asexually (short rhizomes that 

 elongate after flowering) . Flowers of the auricled twayblade bloom in July 

 and the fruit capsules mature within a week of fertilization. Twayblades are 

 pollinated by mosquitos, small moths, beetles, and ichneumonid wasps (van der 

 Pijl and Dobson 1966; and Darwin 1877). The pollen is contained in two simple 

 masses called pollinia, which, in Listera , are explosively released at the 

 touch of a pollinator. A droplet of a glue-like material from the pollinia 

 dries solidly within a few seconds and fixes the pollinia to the pollinator. 

 There is no evidence this species forms a close association with a specific 

 species of pollinator. Twayblades produce seeds profusely. Seed predators 

 probably include insects and small mammals. 



Flooding, peat mining, stream channeling, and logging pose the greatest 

 threats to this species. 



Pale Green Orchis 



The pale green orchis is a threatened orchid of which herbiola is the only 

 variety found in Maine. This species is also placed in the genus Platanthera 

 P. f lava (L.) Lindley var. herbiola (R. Brown) Luer . It grows in low, wet, 

 woods, moist thickets, and along marshy banks. It is often found in shallow 

 water with a thick layer of decaying leaves (Luer 1975). It's range extends 

 from Nova Scotia to Wisconsin, and south to Florida and the Gulf States. The 

 northern variety ( herbiola ) is found from Kentucky and western North Carolina 

 north. It has been found in four locations in the coastal zone: West Dresden 

 in region 2 (1973); Monhegan in region 3 (1964); and Rockport (1935) and 

 Frankfort (1916) in region 4. It has been collected in the adjacent townships 

 of Clinton (1914 and 1916), Vassalboro (1916), and in 20 other areas in Maine. 

 The varieties f lava and herbiola intergrade where their ranges overlap (Luer 

 1975). 



Reproduction in the pale green orchis is entirely sexual. It is pollinated by 

 small moths and Aedes mosquitos (van der Pijl and Dobson 1966). As with 

 Listera, the pollen is borne in two masses; the pollinia, which become 

 attached to the insect. The flowering period is between July and early 

 August. 



Lumbering, flooding, stream channeling, and plant collecting pose the greatest 

 threats to the pale green orchis. 



20-12 



