PLANT SUCCESSION" AND RANGE MANAGEMENT. 



57 



perennial plants on both of these protected plots, low larkspur has 

 increased proportionately much more rapidly than any other ; on the 

 outside range the colonization of the low larkspur has been only 

 m^oderately rapid and in proportion to that of other perennial plants. 

 This difference in aggressiveness of larkspur is accounted for by 

 the fact that the unprotected range is grazed b}" sheep prior to seed 

 maturity.^ As larkspur is fairly palatable to sheep, onlj^ a small pro- 



B — Large mountain brome grass {Bromus 

 marginatus) . 



C — Slender-leaved collomia {Collomia lin- 

 earis). 



D — Low larkspur {Delphinium menzlcs-ii). 



E — Sweet sage (Artemisia discolor). 



F — Spiked fescue (Festuca confines). 



L — Low pea vine (Lathyrus Icucanthus) . 



La — Evening primrose (Lavaiixia fiava). 



N — Chickweed {Alsine jamesiana). 



■ — X — X — Fence. 



S — Tansy mustard {iSophia incisa). 



Sa — ^Mountain elder (Samhiictis microhot- 

 rys). 



T — Dandelion {Leontodon taraxacum). 



Th — Meadow rue {Thalictrum fcndleri). 



V — Tongue-leaved violet (Viola linguae- 

 folia). 



X — Douglas knotweed (Polygonum doug- 

 lasii). 



Y — Plantain (Plantago tweedyi). 



. . ■ Dry gully. 



P — Blue foxglove (Pentstemon procerus). 



Fig. 22. — Character of vegetation on a formerly depleted stock driveway in process of 



recuperation. 



portion of the seed crop is matured on the open range, whereas maxi- 

 mum seed production is secured on the protected area. Being small, 

 comparatively heavy, and without special contrivances favoring dis- 

 tribution by wind or attachment, the seeds drop near the parent plant, 

 where they give rise to new individuals. 



Like certain other species previously discussed, low larkspur holds 

 a more or less conspicuous place in the development of the vegetation 



1 Most larkspurs are grazed with moderate relish by sheep, and, so far as known, with- 

 out serious results. 



