Trifolium Iiicanialum Quadrifolium. 231 
If Trifolium incarnatum with 4-foliate leaves had 
often been mentioned it would therefore seem probable 
that a five-leaved race of it occurs in nature, although 
just as little separated from the ordinary crimson clover 
as the five-leaved race of the ordinary clover is from 
this. 
Latent characters, in my opinion, are often older than 
the species which bear them. I regard the division of the 
leaf into four blades in this case as an atavistic phenom- 
enon, and I believe that this latent potentiality is as old 
as the whole group of clovers 
with trifoliate leaves (Trifolium, 
Mcdicago, Mclilotns etc.), that 
is, older than the individual gen- 
era of this group. In many spe- 
cies this power of reproducing 
quadri foliate leaves may have 
been completely lost, for it is 
mentioned in PENZIG'S book only 
for a relatively small number of 
them. In others, however, it has Fl > ^. Trifolium 
An atavistic pinnate leat. 
persisted to the present day. If 
the trifoliate leaves of the clovers are derived from 
Papilionaceae with pinnate ones, the multi foliate leaves 
which they occasionally produce must evidently be re- 
garded as atavistic phenomena. The correctness of this 
view is proved by those very rare cases in which, in 
the races in question, pinnate leaves appear instead of the 
ordinary multi foliate ones. I have observed this from 
/ 
time to time in my Trifolium pratcnse quinqne folium 
(Fig. 46) and the same thing has been found by other 
authors in Trifolium minus and Trifolium re pens. 
I have myself found 4- and 5-foliate leaves in Medi- 
