Explanations of Plates 1 to 23, Genus Artemisia. 



Plate 18 — continued. 



Artemisia tridcntata parishi. (Drawn from fresh ma- 

 terial from the tv-pe locality, except the flower, 

 which is from type collection, 54010 UC.) 

 (9) Leafy shoot with entire, bidentate, and triden- 

 tate leaves, X 1. 



(10) Portion of a younp inflorescence with drooping 



heads, X 1. The heads on neighboring plants 

 are erect, as in the usual form of typica 

 (see p. 143). 



(11) Flower showing the pubescent achene and 



scattered resin-granules, X 16. 



Plate 19. 

 Artemisia tridentata trifida. (Drawn from fresh ma- 

 terial from southern Wyoming.) 



(1) Branch showing the mostly trifid leaves and 



narrow inflorescences, X 1. 



(2) Habit sketch, X 0.08. 



Artemisia tridentata nova. (Material from Laramie 

 Hills, Wyoming, 517G0 UC.) 



(3) Branch showing the tridentate leaves and 



moderately narrow inflorescences, X 1. 



(4) Shoot with some leaves tridentate, others 



trifid, X 1. 



(5) A very narrow inflorescence, X 1. 



(6) Head, X 8. 



(7) Outer bract of the involucre, X 16. 



(8) Inner bract, X 16. 



(9) Flower with scattered resin-granules, X 16. 

 (10) Style, X 24. 



Plate 20. 

 Artemisia tridentata arbuscula. 



(1) Leafy shoot with 2 inflorescences, X 1. (Ma- 



terial from eastern Oregon, 175216 UC.) 



(2) Leafy shoot showing the more deeply lobed 



leaves of minor variation 10 (p. 140), X 1. 

 (Material from near Donner Pass, Placer 

 County, California, 202223 UC.) 

 Artemisia tridentata rothrocki. 



(3) Stem with narrow inflorescence, X 1. (Ma- 



terial from Tioga Pass, California.) 



(4) Leafy shoot, X 1. (Material from Little 



Cottonwood Creek, California.) 



(5) Stem with typical branching inflorescence, X 1. 



(From the same plant as fig. 4.) 



Plate 21. 

 Artemisia carta. (Drawn from fresh material from 

 Bosler, Wyoming.) 



(1) Branch with leafy shoots, X 1. 



(2) Inflorescence, X 1. 



Plate 21 — continued. 



(3) Inflorescence showing more elongated branches, 



X 1. 



(4) Shoot with leaves of maximum width,' X 1. 



(5) Head, X 8. 



(6) Middle bract of the involucre, X 16. 



(7) Inner bract, X 16. 



(8) Flower, X 16. 



(9) Style, X 24. 



(10) Habit sketch, X 0.03. 



Plate 22. 

 Artemisia rigida. (Drawn from fresh material and 

 photographs from northeastern Oregon.) 



(1) Portion of plant with inflorescences, X 1. 



(2) Head, X 8. 



(3) Bract from the base of tlie involucre, X 16. 



(4) Inner bract, X 16. 



(5) Flower, X 16. 



(6) Style, X 24. 



(7) Three leaves, showing variation in lobing; X 3. 



(8) Leaf of the inflorescence, X 3. 



(9) Habit sketch of entire plant, X 0.125. 

 Artemisia pygmaea. (Material from Pioche, Nevada, 



17947S UC.) 



(10) Twigs, showing the inflorescence; X 1. 



(11) Leaves, X 3. 



(12) Habit sketch, apparently of a plant growing 



on a slope, since the roots are horizontal; 

 X 0.17. 



(13) Inner bract of the involucre, X 16. 



(14) Bract from outer portion of the involucre, X 16. 



(15) Flower, X 16. 



(16) Style, X 24. 



(17) Head, X 8. 



Plate 23. 



Artemisia palmeri. (Drawn from fresh material from 

 La Jolla, Cahfornia.) 



(1) Portion of the inflorescence showing also a 



few of the entire upper leaves, X 1. 



(2) A common type of leaf with five lobes, X 1. 



(3) An upper leaf with three lobes, X 1. 



(4) An upper leaf with a single lateral lobe, 



transitional to the simple leaves of the 

 inflorescence; X 1. 



(5) Head with subtending bracts, X 8. 



(6) Outer bract of the involucre, X 16. 



(7) Inner bract, X 16. 



(8) Disk-flower showing scattered resin-glands on 



the achene and corolla, X 16. The ray- 

 flowers are wanting in this species. 



(9) Style, X 24. 



