A, VULGARIS. 83 



20. A. PLODMANi Rydberg, N. Am. Fl. 34:276, 1916.— .4. vulgaris flodmani. 



21. A. GHiESBRBGHTi Rydberg, 1. c, 271, 1916.— Taken to be an exceptionally large-headed form of A. 

 vulgaris mexicana, the involucres 4 to 5 mm. high, but perhaps better treated as a distinct variety related to 

 mexicana. Known from only a few collections from Chiapas, which is the type locality, and the Federal 

 District of Mexico. 



22. A. GNAPHALODE.S Nuttall, Genera 2:143, 1818. — A. vulgaris gnaphalodes. 



23. A. GNAPHALODES DivERsiFOLiA NbIsoh; Coulter and Nelson, Man. Rocky Mt. 569, 1909.— Based upon 

 A. diver sifolia Rydberg, which see. 



24. A. GORMANi Rydberg, N. Am. Fl. 34:267, 1916. — This is exactly the elatior form of A. vulgaris tilesi 

 with rather narrow leaf-lobes, some of which are again toothed or divided, and only about 10 disk-flowers. 

 The subspecies tilesi must be taken to include some forms with entire leaf-lobes and some with toothed or cleft 

 lobes, as called for by Rydberg's description in the North American Flora. The narrow leaf-lobes of gormani 

 can scarcely be admitted as a character of subspecific importance in a species where the foliage is so variable, 

 and the smaller number of disk-flowers is perhaps due to the age of the type specimens, the heads of which look 

 as though some flowers had been lost. Type locality, Lake Iliamna region, Alaska. 



25. A. GRACiLENTA Nelson, Bull. Torr. Club 27:35, 1900. — A. vulgaris candicans. Heads either sessile 

 and glomerate or short-pediceled; leaves equally white-tomentose on both sides. Type locality, sandy beaches 

 and banks of Yellowstone Lake. 



26. A. GRAVEOLENS Rydberg, Bull. Torr. Club 24:296, 1897. — A. vulgaris discolor, but with greener leaves 

 than in the type and these with slightly broader segments as in the form once called A. incompta Nuttall. 

 (See under A. michauxiana of this list.) The type came from Long Baldy, Little Belt Mountains, Montana, 

 but green plants of this form occur from the northern Rocky Mountains nearly to the Pacific Coast. 



27. A. HERRioTi Rydberg, 1. c, 37:455, 1910. — A. vulgaris heterophylla. Separated from the douglasiana 

 form of this subspecies on the basis of its erect heads with only 5 to 15 flowers and the oblong involucre. A 

 more recent examination of one head from the type reveals a total of 18 flowers (7 ray and 11 disk) which brings 

 the number weO within the limits for heterophylla, as indicated in table 6. Type locality, Edmonton, Alberta. 



28. A. HETEROPHYLLA Nuttall, Trans. Am. Phil. Soc. ii, 400, 1841. Not A. heterophylla Besser, 1834.— 

 A. vulgaris heterophylla. The original description is so drawn as to include both this and subspecies litoralis. 

 The heads are given as " cylindric-ovate and small," which applies better to litoralis, but the type locality is 

 given as "Rocky Mountains by stream," whereas litoralis is closely confined to a narrow coastal strip. A 

 specimen at the herbarium of the Philadelphia Academy of Sciences labeled by Nuttall as from the Columbia 

 Plains and as a type of his heterophylla, is plainly litoralis. Another, in the Gray Herbarium, labeled by Nuttall 

 as from the Rocky Mountains by streams and also as a type of his heterophylla, is just as plainly the more inland 

 form here treated as A. vulgaris heterophylla. The Philadelphia specimen has smaU, ovoid, glabrous heads; 

 the one at the Gray Herbarium has larger, hemispheric, tomentose heads. Since the locality as given on the 

 Gray Herbarium label agrees with that stated by Nuttall in connection with his description, this specimen is 

 taken as the type. (See also under A. hookeriana and A. douglasiana of this list.) 



29. A. HOOKERIANA Besser, in Hooker, Fl. Bor. Am. 1 :322, 1833. — Not positively identified. The original 

 description as well as fragments and tracings at the Gray Herbarium, apparently of the type, indicate a form 

 close to A. vulgaris heterophylla, with heads of maximum size for this subspecies and white stems. The leaf 

 is deeply pinnatifid with acute lobes. The type was collected by Drummond in the Rocky Mountains and 

 therefore, even though it might be accepted as belonging to the same subspecies as the Pacific Coast heterophylla, 

 it represents an outlying form far removed from the center of distribution. It is largely because of these doubts 

 and the facts of distribution that hookeriana is not here taken up as the subspecific name of the common 

 mugwort, which ranges from British Columbia to Lower California and has commonly passed as A. vulgaris 

 var. calijornica Besser and A. heterophylla Nuttall. A. douglasiana Besser is another trivial variation of sub- 

 species heterophylla. In the North American Flora hookeriana and douglasiana are both recognized as species 

 and distinguished from each other on the lobing of the leaf, the former having lower leaves deeply divided into 

 more or less falcate divisions, the latter having lower leaves with shorter lobes or teeth directed forward. In 

 that work hookeriana was stated to occur from Saskatchewan to Oregon, douglasiana from Idaho and southern 

 Washington to southern California. The utter unreliability of leaf-characters in this group has been already 

 demonstrated (p. 41). They do not run parallel with distribution, as is indicated by the presence as far north 

 as Oregon of plants with nearly entire or few-lobed leaves (Grant's Pass, Oregon, July 14, 1887, Howell), while 

 in the south there are plants in which the leaves are deeply cut into spreading lobes (Laton, Kings County, 

 California, October 25, 1919, Hall, and many collections from around San Francisco and Monterey bays), 

 and throughout middle and northern California both forms are common. It is not unusual to find all 

 gradations in leaf-lobing on plants growing close together (see text-figs. 3, 7, and 12). It is true, however, that in 

 southern California, except along the coast, the general tendency is towards entire or short-lobed leaves. The 

 original description of A. douglasiana calls for entire leaves, but this was probably due to the collector having 

 taken only the tops of the plants. 



