622 Validity of the Doctrine of Mutation. 
stock in hybrids of Helianthemum. 1 Hybrid peas may 
be partly green and partly yellow 2 and similar segrega- 
tions have been found by CORRENS and WEBBER on grains 
of hybrid maize. 
But the best known instance of a vegetative segrega- 
tion is furnished by Cytisus Adami (C. Laburnum X 
purpureus), which any one can observe in his garden 
or in parks. The hybrid is absolutely sterile, and all 
the specimens of it are grown from cuttings from one 
single individual. Whether the extraordinary tendency 
to segregate is peculiar to this hybrid as such, or to this 
particular individual, we cannot know. 3 The fact is, 
that this hybrid is intermediate between its two parents 
and besides this produces from time to time buds, of 
which some become strong branches of C. Laburnum 
with its large leaves and long racemes (Fig. 139L), 
whilst from others the delicate, slender and bushy 
branches of C. purpureus arise, bearing their fruits and 
flowers either singly or in small groups (Fig. 140 PV 
The current view is that C. Ad ami is a graft hybrid. 4 
There is, however, neither an historical nor a physiolog- 
ical justification for this view. 5 The original raiser of 
the plant, the Parisian gardener ADAM, seems himself 
to have thought that this form which he put on the 
1 FOCKE, Die Pftansenmischlinge, p. 473. where further instances 
will be found. See also BRAUX, Ver/iingung, p. 336; DARWIN, Ani- 
mals and Plants Under Domestication, etc. Similar facts are afforded 
by Hieracium, O.ralis. Chamacdorea etc. ; see F. HILDEBRAND, Jen. 
Zcitsehrift, Vol. XXIII, 1889, Plate XXV. 
2 F. WELDON, Biomctrika. I, 2, 1902. 
3 See the remarks relating to Datura on the foregoing pages. 
* Intracellulare Pangenesls (Ger. eel.), p. 206. 
5 T have given an historical account of Cytisus Adanii, in Dutch, 
in the Album der Natuur, 1894, Part 7, under the title Adam's Gouden 
Regen. The original source of the historical data is found in Annales 
de h Soeietc horticole de Paris, Vol. VTT, 1830. 
