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157 
it now seems that dessication will adequately explain the origin of the 
staminate flower and excessive protection the origin of the pistillate. 
LITERATURE CITED. 
1. Britton, N. L. Manual of the Flora of the Northern States and Canada, 
1907. 
2. Chamberlain, Charles J. Comparative Study of the Styles of the Com- 
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9. Merrell, W. D. A Contribution to the Life History of Silphium. Bot. 
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10. Nissen, J. Untersuchungen uber den Blutenboden der Compositen. 
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d. d. Bot. Gesell. XXIX 406-416, 1911. 
12. Stadler, P. H. Die Morphologie und Anatomie van Cnicus t>enedictus L. 
Diss. Strassburg, 1908. 71 pp. 
13. Tschirch, A. Sind die Antheren der Compositen verwacksen Oder 
verklebt? Flora 93: 51-55, 1903. 
14. Uexkull-Gyllenband, Margarethe. Phylogenie der Bluthenformen und 
der Geschlechterverteilung bei den Compositen. Bibliotheca botanica. Hept 
LII. 80 pp., 1901. 
15. Warming. Die Blumen der Compositen. Hanstein’s Bot. Abhandlungen 
III Hept 2., 1876. 
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Sympetalous Dicotyledons. VII inferae. Part II Campanulatae, New Phytologist 
XI. No. 8, p. 290, 1912. 
EXPLANATION OF PLATES. 
All drawings were made with Spencer camera lucida, except figures 
1, 2, 5 and 12. The plates are reduced one-half in reproduction. Fig- 
ures 3, 4, 7, 8, 9 and 10 were made with Spencer 16 mm. objective and 
4 ocular. Figure 6 was made with Bausch and Lomb 1 / 12 immersion 
objective and 4 ocular. The original magnifications in diameters were 
