Presumptive Mutations in Wild & Cultivated Plants 59 



A much earlier record of a double wallflower has, however, 

 since been found (Saunders, 1916c). There is a reference to it in an 

 Arabic " Book of Agriculture " of the 12th Century, the statements 

 in which are based on an earlier work probably written about 1073. 

 As we shall see, the records show that doubling is by no means 

 rare in wild species, so it is quite possible that a double wall- 

 flower was taken into cultivation as such. Doubling appears to 

 have occurred at least twice in cultivation. The older, fully double 

 wallflower (Saunders, 1917) was wholly sterile like the double stocks. 

 It appears to have originated only once as a sport, and have since 

 been propagated by cuttings. The partial double is more recent 

 in origin and shows grades of doubling forming a continuous 

 series. This double form is therefore not in the same series with 

 the full double, but represents an independent germinal change. 



Bateson and Miss Sutton (1919) have found greater irregularity 

 in Begonia. A double monoecious $ x single $ gave singles 

 generally dominant, but segregation was irregular and transitional 

 forms appeared. An average of 1 double in 32 was obtained, and 

 back crosses were also irregular. B. Davisii from Peru crossed 

 on common doubles gave only double. This single is believed to 

 be genetically double on the $ side. 



The first double Dahlia is mentioned and figured in a work on 

 the natural history of Mexico, published at Rome in 1651. ' Hence 

 it apparently did not originate in cultivation. There are a number 

 of early American records of wild species with double flowers, some 

 of which may be summarized here. In Saxijraga Virginiensis we 

 have found nine records of double flowers, as follows : (1) A double 

 found near Hingham, Mass., in 1849." (2) Asa Gray 3 found a 

 double at Danvers, Mass., 1866, which continued so from year to 

 year. (3) A specimen found on the Delaware River below Easton 

 with extra petals. 4 This was apparently not fully double. (4) A 

 wild double from Canaan, Conn., was reported by A. Gray. 8 It 

 bore 70 or 80 flowers, all pure white and fully double, without 

 stamens. This very ornamental plant was divided, and part of it 

 cultivated in the Cambridge, Mass., Botanic Garden. (5) Two 

 more specimens were found 8 on the banks of the Schuylkill, near 



1 Card. Chron. 59 : 336, 1916. 



' J. L. R., Amer. Nat. 2 : 610, 1869. 



Amer. Nat. 2: 484, 1869. 



Porter, Thos. C., Bot. Gazette 1 : 5, 1875. 



Amer. Nat. 11 : 366, 1877. 



Martindale, I. C., Amer Nat. 11 : 432, 1877. 



