Vermont Shrubs and Woody Vines 119 



Of the ten groups found in Vermont, four are trees and 

 the others are usually large shrubs, although all of them but the 

 Intricatae may occasionally produce a small shrubby tree. This 

 variable genus is not as yet well understood. Although many 

 species have been described, much good work may yet be 

 done in our field to further the study of the thorns. For the 

 purpose of this work it seemed best to give only a short account 

 of the groups. If one cares to go farther he will find in Rhodora, 

 in the Botanical Gazette and in the New Gray's Manual much 

 information which will be pertinent. It should be noted that the 

 following account deals only with the smaller or shrubby species. 



Key to the groups of shrubby species based on fruiting 

 characters. 

 1. Nutlets pitted on the inner surface 2 



1. Nutlets plain on the inner surface 3 



2. Nutlets deeply pitted Macracanthae. 



2. Nutlets with shallow pits Anomalae. 



3. Fruit hard at maturity 4 



3. Fruit soft at maturity 5 



4. Fruit waxy, petioles smooth Pruinosae. 



4. Fruit not waxy, petioles wtih stalked glands Intricatae. 



5. Fruit ellipsoidal Tenuifoliae 



5. Fruit globose Rotundifoliae. 



Key to the group of shrubby species based on flowering 

 stage. 

 1. Calyx lobes entire or nearly so 2 



1. Calyx lobes serrate 3 



2. Leaves yellow-green slightly hairy, flowers l^/^ — 2 cm. wide, 



anthers, pink Tenuifoliae. 



2. Leaves blue-green, smooth, flowers about 2 cm. wide, anthers 



light pink Pruinosae. 



3. Calyx lobes serrate 4 



3. Calyx lobes deeply serrate 5 



4. Calyx lobes more prominently toothed towards the apex, petioles 



with stalked glands Intricatae. 



4. Calyx lobes equally toothed throughout length, petioles without 



stalked glands Rotundifoliae. 



5. Leaves dark green and shining above, rather thick, veins some- 



what impressed Macracanthae. 



5. Leaves lighter, thinner, veins not impressed Anomalae. 



