C8 SALICACEAE 



1. POPULUS L. 

 Trees with broad leaves. Buds scaly, resinous covered. Filaments 

 distinct. Ovary sessile. Stigmas 2-4, elongated. Capsule 2-4-valved. 



Leaves white, tonientose beneath. 1. P. alba. 



Leaves green beneath. 2. P. thltoides. 



1. P. alba L. Silver-leaf Poplar. A tree often 100° high : leaves 

 ovate-orbicular, sinuate toothed, white-tomeutose beneath : capsules on 

 short pedicels. — Cultivated and spreading by suckers. Independence, 

 Raytown. April. 



2. P. deltoides Marsh. Cotton-wood. 50°-150° high : leaves broadly 

 deltoid, abruptly acuminate, crenulate : petiole laterally llattened : cap- 

 sules long-pedicelled. — Common in river bottoms. April. 



2. SALIX L. Willow. 

 Trees or slirubs with narrow leaves. Buds covered by a single scale. 

 Filaments distinct or united. Ovary sessile or short stipitate. Stigmas 

 2, short. Capsule 2-valved. 



Catkins appearing after the leaves. 

 Stamens three to five. 



Leaves green on both sides. 1. S. nigra. 



Leaves glaucous, whitened beneath. 



Leaves 7'^ or less wide. 2. S. longipen. 



Leaves 6"-14'' wide. 3. S. amygdaloiJes. 



Stamens two. 



Leaves on petioles 2^^-4'' long ; a tree. 4. S. alha rileJIina. 



Leaves almost sessile : a shrub. 5. S. interior. 



Catkins appearing before the leaves. 



Capsule densely pubescent. 6. S. humilis. 



Capsule glabrous. 7. S. cordata. 



1. S. nigra Marsh. Bla(;k Willow. 15°-100° high : leaves lanceo- 

 late, long-attenuate, downy when young, at length green and glabrous 

 except on the veins beneath, serrulate : petioles V^-Z" long : fruiting 

 aments usually dense : capsules twice the length of their pedicels. — 

 Common along streams. April -May. 



2. S. longipes Shuttlw. A shrub or small tree : leaves lanceolate, 

 long-acuminate, silvery-white and usually pubescent beneath, on petioles 

 V-l'^ long : aments loosely flowered : capsules on pedicels of nearly their 

 own length. — Kocky beds of streams throughout the western half, but 

 not abundant. April-May. 



3. S. amygdaloides Anders. IJke S. Imtgijirs but with broader, long- 

 petioled, nearly glabrous leaves : atii)ules small : aments loose : civpsules 

 on long lilifoim pedicels. — Common along streams, especially in the 

 Missouri bottoms. April-May. 



4. S. alba vitelllna (L.) Koih. Wiiitic Willow. 50°-90° high: 

 leaves oblong lanceolate, glabrous above when mature, whitish beneath, 

 serrulate : aments closely flowered ; ciipsules almost sessile. — Adventized 

 occasionally near Slieflield and Independence. April -May. 



