A. ABROTANUM. 51 



18, the outer ones linear-lanceolate, nearly equaling the inner ones, with herbaceous 

 medial line and broad scarious margins, canescent or somewhat tomentose, the rest 

 broadly elliptic, mostly scarious and less pubescent; receptacle naked; ray-flowers 5 to 

 15, corolla about 1.5 mm. long, narrowed upwards; disk-flowers 10 to 20, fertile, corolla 

 campanulate, 1.5 to perhaps 2 mm. long, 5-toothed, glabrous; style-branches of disk- 

 flowers flat, truncate, erose at summit; achenes nearly oblong but broadest at the truncate 

 summit, 4- or 5-angled, glabrous. 



Southern Europe and the Orient ; occasionally escapes from gardens in North America. 

 Type locality, Syria. Collections: McDonough, New York, July, 1886, Coville (US); 

 Washington Island, Wisconsin, September 13, 1889, Schuette (Gr); Benson County, 

 North Dakota, August 3, 1913, Lunell (US); Indian Head, Assiniboia, Macoun 10986 

 (NY). 



MINOR VARIATIONS. 



Artemisia procera Willdenow, Sp. PI. 3: 1818, 1804. European and Asiastic botanists have almost uni- 

 versally treated this as a species distinct from A. ahrolanum, but the two are so closely similar in all essential 

 characters that its reduction to subspecific rank would better express their botanical relationship. It is less 

 shrubby than this species, the stems are said to be more decidedly erect, and the leaves are more finely dis- 

 sected. The involucre is described as only subcanescent or even glabrous (Willdenow) as contrasted with the 

 densely cinereous or even tomentose involucre of ahrolanum, but apparently all degrees of density of pubescence 

 occur. A. procera was collected many years ago at Buffalo, New York, by Clinton, and was said then to be 

 established in two or three places as a garden escape. A number of varieties are recognized in the Old World, 

 and similar forms may be expected in ahrolanum. These are based upon such characters as the shape and 

 size of the head, the presence or absence of pubescence on the corollas, and the amount of odor. Eight of 

 these varieties are described by Besser (in De Candolle, Prodr. 6: 108, 1837). 



RELATIONSHIPS. 



This common Old World plant has given its name to the section Ahrolanum and with 

 scarcely a doubt is one of the most primitive species of the genus. This conclusion is 

 based upon the theory that the other sections arose from this one, as outlined in the 

 chapter on subgenera and sections, and also upon the shape and ribbing of the achenes. 

 These achenial characters ally abrotanum with pontica and californica, as is set forth 

 under the latter species where reasons are also given for considering this the most primi- 

 tive group of the section. 



The size of the heads and flowers and the number of the latter are all somewhat 

 smaller as given in the above description than those of Rydberg in the North American 

 Flora. Our figures are based upon 10 sheets, about half of which are of introduced 

 plants, the remainder being European. 



ECOLOGY AND USES. 



The life-form of Artemisia abrotanum is that of the shrub or bush, resembling A. 

 californica. Its role in vegetation appears to have received no attention in its native 

 area. In America the species is cultivated and has escaped into waste places. 



In old English gardens especially, but also in American gardens, the southernwood, 

 or old man, as this species is commonly called, is much grown as an ornamental shrub. 

 Its value for this purpose lies in its strong bushy growth and in the pleasant odor of the 

 herbage. At the Canada experimental farms it is considered as the best shrub for wind- 

 breaks, while in Colorado it has been used as a nurse crop in reforestation, although it 

 there kills down in winter and so is of only temporary use. The plants are easily grown, 

 both from seeds and from cuttings taken in early summer, and thrive in any ordinary 

 garden soil. They are somewhat tender as regards cold, but are grown as far north as 

 the Canadian boundary on both sides of the continent. The leaves have a pleasant taste 

 and were formerly much used for the preparation of a decoction employed as a tonic and 

 anthelmintic. 



