228 GENUS CHRYSOTHAMNUS. 



specimens can not be definitely assigned to a particular subspecies. Subspecies pinifoHus 

 most closely resembles graveolens, but has much narrower 1-nerved leaves. It is abundant 

 on alkaline plains of the southern Rocky Mountain region. From western Wyoming 

 and Colorado to Oregon and western Nevada, that is, almost throughout the Great 

 Basin, the commonest subspecies is consimiHs. This is a more slender plant than 

 pinifoUus and the corolla-lobes are 1 to 2 mm. long, as contrasted with 0.5 to 1 mm. 

 for that subspecies. Perhaps because of their length, the corolla-lobes are inclined to 

 spread or recurve. The inflorescence is often quite elongated, although in some cases, 

 especially in dwarfed plants, it is as rounded as in the common form of pinifoHus. To 

 the southwest of the consimiHs area, and especially in the alkaline valleys of west central 

 Nevada and eastern California, is found the more robust subspecies viridulus, a form 

 in which the corolla-lobes attain the length of 2 to 2.5 mm., this being the longest in 

 the genus. The forms and relationships of this were discussed by its author as follows 

 (Hall, Univ. Calif. Publ. Bot. 7:178, 1919): 



"This is the common form on alkaline flats in southern Mono County and in Inyo County, California, and in 

 western Esmeralda County, Nevada, although there are many slight variations from the type as described 

 above. Almost every valley exhibits forms not exactly like those in any other. The variations are chiefly in 

 habit, pubescence, leafiness, size and shape of inflorescence, shape of bracts, and length of corolla-lobes. The 

 plants range in height from a few dm. to nearly 3 m., but are always taller than broad unless abnormal; the 

 corollas vary from 8 to 10 mm. in total length; the corolla-lobes are seldom shorter than 2 mm., yet in two col- 

 lections there are some flowers with lobes only 1.7 mm. long; although the involucres of the type are only 6 to 

 7 mm. long, they vary in other specimens to 8 or even 9 mm. ; the mature pappus is 7 to 9 mm. long. * * * 

 As to relationships, viridulus probably is a southwestern derivative of consimiHs (or vice versa), from which it 

 differs in the larger corollas with longer lobes, the thicker, more robust, and rigid twigs and leaves, the heavier 

 and more rounded inflorescence, and the stronger odor of the herbage. These characters are far from constant 

 at aD stations. The length of the corolla-lobe is the most satisfactory. Of twenty-seven collections taken 

 throughout the established range of the variety, only five have corolla-lobes 2 mm. or less long; of twenty-two 

 collections from the range of consimiHs none exhibit corolla-lobes of over 2 mm. in length; where the ranges 

 meet, as around Mono Lake and at Sodaville, Nevada, intermediate sizes are frequent and here the other differ- 

 entiating characters also intergrade." 



It should not be inferred from the above that these varieties actually intergrade, 

 because some of their characters do so. What appear to be intergrades may in reality 

 be hybrids. On the other hand, the phylogenetic line from graveolens through pinifoHus 

 and consimiHs to viridulus seems reasonably well established. 



Two subspecies, both derivatives of viridulus, are indicated as lying outside of the 

 graveolens circle, because of the marked development of certain features. In ceruminosus 

 the tips of the involucral bracts are abruptly narrowed and recurved. No intermediate 

 stages are known, but the form has been collected only twice. The subspecies mohavensis 

 is a southern and far western derivative of viridulus and belongs to higher, less alkaline 

 slopes. It is distinguished by an exceptionally long involucre, the sharply keeled bracts 

 of which fall into very well defined vertical rows. It was first described as sparsely 

 leafy or leafless, but there is a tendency throughout the graveolens group toward an early 

 dropping of the leaves. Intermediates are sometimes found in which the habit is that 

 of ynohavensis, except for the more persistent leaves, the bracts are in sharply defined 

 vertical rows, but acute as in viridulus, and the involucre and corolla-lobes are exactly 

 intermediate in length (Oak Creek, westerly side of Owens Valley, California, Hall 

 10611). 



In taking up the third main line, it is found to lead to a group of only two subspecies, 

 namely, junceus and turhinalus. These are almost unique in the species in that their 

 corolla-lobes are externally villous with long delicate hairs. This character reappears, 

 however, in a form of subspecies albicaulis (see minor variation 63), in one subspecies 

 of C. howardi, and in C. pyramidatus. Subspecies junceus is a nearly leafless, little- 



