TREES AND SHRUBS 



147 



KEY TO THE TRIBES HERE LISTED. 



Anthers not caudate at the base; style-branches 

 either truncate or tipped with an appen- 

 dage. 

 Heads rayless; flowers perfect; flowers white 



or very pale yellow. 

 Heads mostly radiate. 



Style branches of perfect flowers flat or 

 tipped with a distinct appendage; leaves 

 mostly alternate. 

 Style branches of perfect flowers truncate 

 or appendaged, not flattened; leaves 

 often opposite. 

 Involucre not scarious. 

 Pappus never capillaria. 

 Receptacle chaffy. 

 Receptacle not chaffy. 

 Pappus capillaria. 

 Involucre scarious; pappus not capillary. 

 Aethers caudate at the base; style branches 

 neither truncate nor appendaged; heads not 

 radiate. 



II. EUPATORIEAE. 



III. ASTEREAE. 



V. Heliantheae. 



VI. Helenieae. 

 VIII. Senecioideae. 



VII. Anthemideae. 



IV. INULEAE. 



KEY TO THE GENERA HERE LISTED. 



Tribe II. Eupatorieae. 



Bracts of the involucre' herbaceous neither 

 striate nor nerved; low shrubs with small 

 heads of large white flowers; leaves entire. 



Bracts of the involucre not herbaceous, striate 

 nerved, flowers small pale yellowish white 

 rather numerous in the head; leaves toothed. 



1. Carphochaete. 



COLEOSANTHUS. 



Tribe III. Astereae. 



Heads unisexual, dioecious, discoid, pappus of 

 the stamenate flowers with clavate tips; 

 flowers mostly white. 3. 



Heads of perfect flowers, at least in part, 

 flowers yellow. 

 Heads without rays. 4. 



Heads radiate. 5. 



Baccharis. 



Chrysothamnus. 

 Chrysoma. 



Tribe IV. Inuleae. 



A single genus with, dioecious pink flowers in 

 discoid heads. 6. 



Berthellotia. 



Tribe V. Heliantheae. 



Heads discoid. 



Heads of two kinds on the same plant; 

 staminate heads several: pistillate usual- 

 ly solitary. 



Htmenoclea. 



