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1901 | SOME PLANT ABNORMALITIES 345 
II, ABNORMAL FOLIAGE LEAVES. 
One of the most common abnormalities in Pelargonium is 
the formation of peltate and funnel-shaped leaves by the growth 
of leaf tissue where there is normally a sinus. On a specimen 
which had been observed to produce a number of peltate leaves, 
there was also found the 
exceedingly interesting form 
shown in figs. rand 2. The 
petiole was about 1.5 times 
as broad as a normal petiole 
and bore two perfectly formed 
blades. These blades were 
united from base to margin 
along a single vein and were 
placed with the under sides 
opposed to each other. This 
leaf gives an excellent illus- 
tration of Bateson’s*t (1894) 
law of reflection, 7. ¢., in the 
duplication of an organ the 
arrangement of the parts is 
the reverse of the arrange- — 
ment of homologous parts in 
the normal organ. So perfect 
was the reflection in this case 
that the more minute details 
of outline were reproduced 
almost as perfectly as in a 
mirror, 
In a leaf of fTicoria sp. 
(fig. iar collected several 
years ago by the writer, the 
terminal leaflet was so regularly and deeply lobed as to be 
almost compound. This modification was decidedly ‘‘progres- 
Sive,” although it occurred in the terminal leaflet, where, as 
‘ oe BATESON, Material for the study of variation, 474-575. London and New 
or 
1G. 3.— Leaf of Hicoria sp. showing 
a deeply lobed terminal leaflet. 
