82 Sudden Appearance and Constancy. 
out ligulate florets. From these plants I only harvested 
the poorest possible seed on the latest branches after 
cutting away the main stem and the stronger branches; 
but from this seed, as before, I obtained nothing but 
Discoidea (750 plants in 1899). 
Flowerheads without, or almost without, rays also 
occasionally occur in races usually normal in this respect. 
Examples of this have occurred in my experimental gar- 
den in Chrysanthemum coronarimn, Coreopsis tinctoria, 
Dahlia striata nana and others. 1 
In the first volume I cited numerous examples of 
constant varieties 2 and showed 3 that many of them were 
certainly one or two centuries old ; in fact as old, or 
probably even older than, the cultivation of their species 
itself. The varieties are generally as constant as the 
wild elementary species, of which Draba vcrna and Viola 
tricolor* w^ere cited as examples. Belonging to the same 
group are the two remarkable types, which HERMANN 
MULLER has distinguished in Iris Pseudacorus, of which 
the one with narrow openings to the flower is adapted 
for pollination by Rhingia, whilst the other is adapted 
for pollination by bumble bees ; 5 IRWIN LYNCH has re- 
cently compiled a very complete and valuable list of 
1 Further examples are given by MURR, loc. cit. 
~ See p. 196. Examples are afforded by GMLLON-strawberries 
(Vol. I, Fig. 7, p. 34) and by Chelidonium laciniotnin (Vol. I, Fig. 
36, p. 190). 
3 On page 183 of the first volume will be found a list of the vari- 
eties known to MUNTING (1671) and still cultivated. 
4 See Vol. I, Figs. 3 and 4, pp. 22 and 23. For the constancy of 
the elementary species of Viola tricolor see also V. B. WITTROCK, 
Viola Studicr in Acta Horti Bergiani, Vol. II, No. I, 1897 (Cultures 
extending over three years). 
H. MULLER, Die Bcfruchtung der Blumen, p. 68. 
