INTRODUCTION. 13 
4. Spirdnthes. Lip ascending and embracing the column 
below, 2 callosities at the base. Flower somewhat ringent ; 
sepals and petals all narrow, mostly erect or connivent. 
Leaves near the bottom or at the base of stem. Roots clustered— 
tuberous. A twisted spike of numerous small flowers. 
S. latifolia, S. Romanzoviana, S. cérnua, S. gramtinea, S. 
gracilis, S. stinplex. 
5. Listera. Lip flat, spreading or pendulous, 2-lobed at the 
apex. Sepals and petals nearly alike, spreading or reflexed. 
A pair of opposite leaves in the middle of the stem. Roots 
fibrous. A raceme of numerous small flowers. 
L. cordiata, L. convallarioides. 
TriseE II]. ARETHUSEA, MALAXIDEA, &c. Anther 
terminal and inverted (except in No. 11) like a lid over the 
stigma, deciduous. 
* Pollen powdery or pulpy, in 2 or 4 delicate masses: no gland. 
6. Arethisa. Lip bearded, its base adherent to the linear 
column. Pollen masses 4. Flower ringent , sepals and petals 
nearly alike, united at base, ascending and arching over the 
column. Leaf solitary. Scape, from a globular solid bulb, 
bearing usually a single flower. 
A. bulbosa. 
7. Pogonia. Lip more or less crested, free from the club- 
shaped column. Pollen masses 2. Flower irregular; sepals and 
petals separate. A single leaf in the middle of stem, or 
several either alternate or in a whorl at the summit. Root a 
cluster of fibres or oblong tubers. Flowers solitary or few in 
number. 
P. ophioglossoides, P. pindula, P. vertillata, P. affinis. 
8. Calopdgon. Lip bearded, stalked, free: column winged at 
the apex. Pollen masses 4. Flower with the ovary or stalk 
not twisting, therefore presenting its lip on the upper or inner 
side. Sepals and petals nearly alike, spreading, distinct. A 
