34 GENUS AKTEMISIA. 



ORIGIN AND DEVELOPMENT OF THE SECTIONS. 



The first attempt at a systematic arrangement of species now referred to Artemisia 

 was that of Tournefort in the latter part of the eighteenth century. This early botanist 

 pointed out certain characters of some importance, such as the pubescence or the lack 

 of it on the receptacle, and published a synopsis of the forms known at that time (Inst. 

 Rei Herb., 457-460, 1700). These were arranged under three genera, namely. Absin- 

 thium, Ahrotanum, and Artemisia. Since Tournefort's system was based largely upon 

 gross external characters, and especially upon aspect, it led to unnatural groupings, 

 which were abandoned by later workers in the Compositae, although his generic names 

 have been retained for certain of the sections.' 



Linnaeus, in the Species Plantarum, united Tournefort's three genera under the one 

 name of Artemisia, thus establishing the genus as now generally accepted. He made 

 only specific use of the receptacular character indicated by Tournefort and based his 

 divisions of the genus, which were not indicated by section names, upon the unimportant 

 characters of habit, inflorescence, and foliage. 



A notable advance was made when Cassini established the genus Oligosporus in 1817 

 to accomodate those Artemisias in which the flowers in each head are of two sorts, i. e., 

 marginal pistillate flowers and central perfect ones, the latter with abortive or at least 

 sterile achenes. This group corresponds to the present section Dracunculus. The other 

 species were all assigned to the genus Artemisia, Absinthium not being recognized. 

 Cassini's treatment was adopted by Lessing (Synopsis Gen. Comp., 264, 1832), who 

 also recognized three subgenera of Artemisia, based upon features which had in the 

 meantime been emphasized by Besser. 



While all of the above workers made certain contributions toward a natural arrange- 

 ment of the species, it was more than a hundred years after the publication of Tourne- 

 fort's studies before a rational and comprehensive natural system was proposed. This 

 was by the Russian botanist Besser, who published his results in various papers, including 

 the first part of what was designed to be an extensive and fully illustrated monograph 

 of the genus. 2 



The monograph projected by Besser was never completed, because of his death in 

 1842, but a masterly summary of his studies is presented in DeCandoUe's Prodromus 

 (6:93-127, 1837). The subdivisions of the genus as established by Besser, together with 

 the characters assigned are as follows: 



Section I. Dracunculus. Heads heterogamous; marginal flowers pistillate (and fertile) ; central flowers perfect but 



sterile; receptacle glabrous. 

 Section II. Seriphidium. Heads homogamous (flowers all perfect and fertile) ; receptacle glabrous. 

 Section III. Ahrotanum. Heads heterogamous; marginal flowers pistillate (and fertile); central flowers perfect and 



fertile; receptacle glabrous. 

 Section IV. Absinthium. Heads heterogamous; marginal flowers pistillate (and fertile) ; central flowers perfect and 



fertile; receptacle hairy. 



Although Besser apparently missed the evolutionary significance of his classification, 

 it has the decided virtue of being natural. It is based primarily upon fundamental 

 differences in floral structure, and therefore always will be used as the basis for any 



'Gaertner, Meyer, and Scherbius (Fl. Wetterau 3 : 196, 1801) retain the Tournefortian genus " Absynihium" with one 



species, namely A. vulgariua Bauhin, that is, A. absinthium Linnaeus. 

 •Besser, W.S. 1829. Synopsis Absinthiorum. Bull. Soc. Imp. Mosc. 1 : 219-265. 



. 1831. de Seriphidiis seu de sectione Ilia Artemisiarum Linnaei. Bull. Soc. Imp. Mosc. 7 : 1-46. 



. 1834. Tentamen pe Abrotanis seu de sectione Ilda Artemisiarum Linneai. Nouv. Mem. Soc. Mosc. 3; 1-92. 



. 1835. Dracunculi seu de sectione IVta et ultima Artemisiarum Linnaei. Bull. Soc. Imp. Mosc. 8 : 1-95. 



. 1836. Supplementum ad synopsin Absynthiorum tentamen de Abrotanis, dissertationem de Seriphidiis atque 



de Dracunculis. lb. 9 : 1-115. 



. 1841. Revisio Artemisiarum Musei Regii Berolinensis, cuius partem oonstituit Herb. Wildenovianum instituta. 



Linnaea 15 : 83-111. 



. 1845. Monographae Artemisiarum, Section I. Dracunculi frutescenlee. Mem. Sav. Etr. St. Petersb. 6 : 1-44. 



