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AN UNUSUAL PLANT OF CHEIRANTHUS 
CHEIRI L. 
By ETHEL M. POULTON, M.Sc. 
University of Birmingham 
(With 16 figures in the text) 
I N May, 1921, the writer observed a curious plant of Cheiranthus 
cheiri growing in the garden of Merion Lodge, Hagley, Worcester¬ 
shire. On examination, the plant was found to exhibit interesting 
deviations from the usual structure. 
Though the inflorescence was of the normal racemose type the 
general appearance of the plant was quite unlike an ordinary wall¬ 
flower. This was partly due to the inconspicuous nature of the flowers. 
The petals were greenish-yellow, simple in shape, showing no differen¬ 
tiation into limb and claw, somewhat concave, and much reduced 
in size. Indeed, they were smaller than the sepals and therefore 
almost enclosed by the calyx (Figs. 1, 1 a). The sepals were of the 
typical shape, size and number (2 + 2; 2 saccate), but were inclined 
to be petaloid. Their margins and apices were usually yellowish. The 
flowers gave the impression of unopened flower-buds rather than 
mature specimens. Sepals and petals had dropped from the oldest 
flowers, but no fruits appeared to be forming. This circumstance may 
probably be correlated with the absence of an attractive corolla. Self- 
pollination could not occur for reasons which follow. 
The most striking feature of the flowers was the entire absence of 
functional stamens and their replacement by carpels in various stages 
of development, a stigma and minute ovules being formed in many 
cases. The characteristic number (6) was everywhere preserved, and 
often the usual arrangement (2 + 4) could be observed. Another 
curious feature was the tendency of the rudimentary carpels to fuse 
with the central gynsecium forming a composite structure (Figs. 2, 3, 
6, 11, 13) x . This fusion was partial or complete, both as regards 
individual “staminate carpels” and the whorl as a whole. Where 
such fusion occurred the seam was usually well marked. The car- 
1 In Figs. 2, 3, 6, 10, 11, 12, the calyx and corolla have been removed. 
