132 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



16. APLECTRUM Torr. 



1. Aplectrum hyemale (Muhl.) Torr. Ptjtty-root. 



Rich woods. May-June. Northern and eastern N. Amer. (A. spicatum II. S. P.) 



17. TIPULARIA Nutt. Crane-fly orchis. 



1. Tipularia unifolia (Muhl.) B. S. P. 

 Medium rich oak woods. July-Aug. Eastern U. S. {T. discolor Nutt.) 



33. SAURURACEAE. Lizard's-tail Family. 



1. SAXJRTJRTJS L. 



1. Saururus cernuus L. Lizard's-tail. 



Swamps and shallow water; common. June-Aug. Eastern U. S. 



A rather showy tall plant with heart-shaped leaves and long slender recurved 

 spikes of small white flowers. It has a ginger-like odor. A characteristic colony of 

 plants is shown in plate 21. 



34. SALICACEAE. Willow Family. 



Bracts of the catkins entire or obscurely toothed; stamens few (1-10); stigmas short; 



bud scale 1 ; leaves much longer than broad 1. SALIX. 



Bracts deeply and sharply toothed; stamens numerous; stigmas elongate; bud 



scales several; leaves broad, often as broad as long 2. POPULUS. 



1. SALIX L. Willow. 



The following species are often cultivated, and isolated indi\dduals may be found 

 in waste places: Salix purpurea L., S. pentandra L., and 5. caprea L. 



KEY TO SPECIMENS WITH CATKINS. 



Catkins stalked, appearing with the leaves or after them; capsule glabrous (hairy 

 when young in S. interior). 

 Catkins appearing long after the leaves, often clustered, terminating long leafy 

 twigs. Leaves linear or broadly linear, remotely and minutely toothed, green 

 on both sides, more or less hairy when young; stamens 2; shrub. 



1. S. interior. 

 Catkins appearing with the leaves, solitary, terminating short leafy stalks. 



Scales of the catkins brown, at least at the tip, persistent; filaments glabrous. 

 Catkins nearly sessile; leaves lanceolate or broadly lanceolate, closely 



serrate, glabrous, pale beneath; shrub 7. S. cordata. 



Scales pale yellow, deciduous; filaments hairy. 

 Stamens 3-7; pedicels 1-3 mm. long; slirubs or small trees. 



Leaves narrowly lanceolate, green on both sides 2. S. nigra. 



Leaves broader, glaucous beneath 3. S. wardi. 



Stamens 2; pedicels less than 1 mm. long; trees. Leaves lanceolate, glaucous 

 beneath. 

 Twigs long, pendulous, tough. Capsule nearly sessile; leaves linear-lanceo- 

 late, glabrous, minutely serrate 6. S. babylonica. 



Twigs short, not pendulous, fragile at the base. 



Capsule short-pediceled; leaves glabrous or nearly so, coarsely serrate; 



petioles glandular 4. S. fragilis. 



Capsule sessile; leaves usually silky, even in age, finely serrate; petioles 

 Bcarcely glandular 5. S. alba. 



