The mutation theory; experiments and observations on the origin of species in the vegetable kingdom . nt potentiality is as oldas the whole group of cloverswith trifoliate leaves {Tvifoliuin,Medicof/o, Mclilotus etc.), thatis, older than the individual gen-era of this group. In many spe-cies this power of reproducingquadrifoliate leaves may havebeen completely lost, for it ismentioned in Penzigs book onlyfor a relatively small number ofthem. In others, however, it has])ersisted to the present day. Ifthe trifoliate leaves of the clovers are derived fromPapilionaceae with pinnate ones, the multi
The mutation theory; experiments and observations on the origin of species in the vegetable kingdom . nt potentiality is as oldas the whole group of cloverswith trifoliate leaves {Tvifoliuin,Medicof/o, Mclilotus etc.), thatis, older than the individual gen-era of this group. In many spe-cies this power of reproducingquadrifoliate leaves may havebeen completely lost, for it ismentioned in Penzigs book onlyfor a relatively small number ofthem. In others, however, it has])ersisted to the present day. Ifthe trifoliate leaves of the clovers are derived fromPapilionaceae with pinnate ones, the multifoliate leaveswhich they occasionally produce must evidently be re-garded as atavistic phenomena. The correctness of thisview is proved by those very rare cases in which, inthe races in question, ])innate leaves appear instead of theordinary multi foliate ones. I have observed this fromtime to time in my Trifoliuni pratcuse qiiijigncfoliitm(Fig. 46) and the same thing has been found bv otherauthors in Trifoliuni in in us and Tri folium re pens. I have mvself found 4- and 5-foliate leaves in Mcdi-. Fig. 46. Trifoliuni f^ atavistic pinnate leaf. 232 Non-Isolabic Races. cogo liipuliua, whilst Braun has observed them In They are well known in T. pratcnsc and , and Wydler has recorded 4-foliate leaves inLotus major and Tctragonolobiis biflonis. In some suc-cessive sowings which 1 made with Medicago lupulina Ifound the character to be inherited although in a mod-erate degree only, but I have not continued the experi-ment. But let us return to the crimson clover. The questionis, what prospects were present at the beginning of theex])eriment, and what may be expected from such ex-periments in general ? There are three main possibilitiesto be considered. We may find at the beginning of theexperiment (See § 3 p. 20) : 1. A race which often exhibits the anomaly in ques-tion, and bears it as a heritable character, i. e., an ever-sporting variety; 2. A half-race
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