ASTRANTHIUM AND RELATED GENERA ESTHER LOUISE LARSEN Formerly Assistant Professor of Botany, University of Montana Formerly Jessie R. Barr Fellow in Botany, Washington University Monographic studies of Aphanostephus and Achaetogeron havemade it necessary to investigate some of the related genera,particularly as to the value of certain morphological characterswhich are used in generic differentiation. The genera are quitesimilar in habit but the pappus, which furnishes importantdiagnostic characters, varies greatly within the group and is onthe whole inconspicuous. For this reason it is necessary to makemicroscopic studies of the minute achenial and pappus charactersupon which the differentiation of genera is primarily dependent.In this connection it was desirable to study Astranthium andKeerlia in detail; and it seems advisable to put on record theresults which have been obtained relative to these genera. Astranthium, a genus of the Compositae belonging to thetribe Astereae, was described by Nuttall in 1841.1 It containedbut one species, A. integrifolium, based on Bellis integrifoliaMichaux.2 The 'Flora of North America,' published by Torreyand Gray in 1842, relegated Astranthium to synonymy. Sincethat time American and Mexican species have been merged withthe genus Bellis3 which is indigenous to the Old World andespecially to Europe. Three South American species have beendescribed by Vellozo4 as occurring in Brazil. Two of these,Bellis campestris Vell. and B. pedunculata Vell., may well bemembers of the genus Spilanthes. The relationship of the third,Bellis scandens Vell., is unknown to me. Bellis perennis L. is an attractive plant, and for this reasonit has been cultivated in the north Atlantic states where it hasbecome naturalized. The American species which have beenreferred hitherto to the genus Bellis are so strikingly different that itseems strange the two generic elements should have been regarded 1 Nutt. Trans. Am. Phil. Soc. N. S. 7: 312. 1841. 1 Michx. FI. Bor. Am. 2: 131. 1803. 3 Torr. & Gray, FI. N. Am. 2: 189. 1842. Vell. Fl. Flum. 8: pl. 124-126. 1827; text, pp. 338, 359, ed. 1881. Issued April 29, 1933.ANN. Mo. BOT. GARD., VOL. 20, 1933. (23)
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