992 Compositae Artemisia 



by underground stems since it is found so sparingly and about the site of 

 a former habitation. 



Nat. of Eu. ; N. S. to Minn., and Oreg., southw. to Ga., Mo., and Nev. 



la. Tanacetum vulgare L. f. crIspum (L.) Fern. (Rhodora 38: 235. 

 1936.) The remarks and distribution given for the species apply also 

 for this form. 



9358. ARTEMISIA [Tourn.] L. Wormwood 



[Hall and Clements. The Phylogenetic Method in Taxonomy, pp. 31-156. 

 Carnegie Institution of Washington Publication 326. 1923.] 

 Receptacle villous-pubescent; leaves 2 or 3 times pinnately parted; heads 2-3 mm high, 



usually wider than high 1. A. Absinthium. 



Receptacle glabrous. 



Leaves glabrous or nearly so on both surfaces, 1-3 times pinnatifid or dissected. 



Leaves once pinnatifid, the segments 1-4 mm wide; flowers on short, leafy axillary 



spikes or in glomerules, the clusters much shorter than the leaves; plants 



biennial 2. A. biennis. 



Leaves more than once pinnatifid or pinnately parted; the segments mostly less 

 than 1 mm wide. 

 Heads about 4 mm wide; involucre pubescent; plants perennial. (See excluded 



species no. 677, p. 1102) A. Abrotanum. 



Heads 2-3 mm wide; involucre glabrous; plants annual or biennial. 



Ultimate segments of leaves mostly about 1 mm long or 2-3 mm long; central 



flowers perfect; annual 3. A. annua. 



Ultimate segments of leaves linear, 5-20 mm long; central flowers sterile; 



biennial 4. A. caudata. 



Leaves densely woolly on one or both surfaces. 



Blades pinnately parted into 5-7 narrow, entire segments. (See excluded species 



no. 679, p. 1102) A. Carruthii. 



Blades lanceolate or linear, serrate or entire, not pinnatifid (sometimes the basal 

 leaves pinnatifid). 

 Leaves green and glabrate above, at least in age, lanceolate, entire or the lower 

 ones pinnatifid with lanceolate, linear-lanceolate, often falcate divisions; in- 

 volucre about 3 mm high; achenes about 1 mm long. (See excluded species 



no. 681, p. 1102) A. ludoviciana. 



Leaves white-tomentose on both surfaces. 



Involucres 3-4 mm high, 2-3.5 mm wide; upper leaves linear and entire, the 

 lower ones oblanceolate, usually serrate toward the apex, 5-10 cm long; 



achenes about 1 mm long 5. A. gnapJvalodes. 



Involucres 4-5 mm high, 4-7 mm wide; leaves linear or linear-lanceolate, entire, 

 6-15 cm long. (See excluded species no. 680, p. 1102) A. longifolia. 



1. Artemisia Absinthium L. Common Wormwood. Map 2175. There 

 are five reports of this species having escaped to roadsides, and I have 

 seen it a few times and collected it once. I believe it may be considered 

 established, especially in the sandy areas of northern Indiana. 



Nat. of Eu.; Newf. to Hudson Bay and Mont., southw. to N. C, Ohio, 

 and N. Dak. 



2. Artemisia biennis Willd. Biennial WORMWOOD. Map 2176. Re- 

 ported from 14 localities within the state and three authors report it as 



