202 PRINCIPLES OF BOTANY, ETC. 
Green into red in 
Ribes Grossularia. 
Black into green in 
Sambucus. 
The seeds of plants likewise frequently change 
from one colour to another; the poppy, (Papaver), 
has both black and white seeds. 
The seeds of papilionaceous flowers are most sub- 
ject to vary in colour. 
§ 202. 
The leavés are in some plants naturally spotted 5 
but the spots are not always constant; they fre- 
quently disappear altogether. Of this we have ex- 
amples in the following : 
Leaves with black spots. 
Arum, Polygonum, Orchis, Hieracium, Hypochaeris, 
Leaves with white spots. 
Pulmonaria, Cyclamen. 
Leaves with red spots. 
Lactuca, Rumex, Beta, Amaranthus. 
Leaves with yellow spots. 
Amaranthus. 
The leaves of some plants become red in autumn, 
as those of Rumex: others at times produce leaves 
wholly red, as Angelica, Fagus, Beta, Amaranthus. 
Most plants change into yellowish green, light green 
or dark green from excess of heat, or of cold, from 
defect in the structure of the vessels, or from va- 
riety of soil and situation. From similar circum- 
stances, the margin or centre of a leaf is subject to 
change. Gardeners are fond of such plants, which 
they 
