452 



The Journal of Hereclir\- 



SEEDLINGS OF THE MCDONALD BLACKBERRY 



The McDonald Blackberry is supposed to be a natural hybrid. It is diffuse and spiny in 

 growth. Two thousand seedlings of this berry were grown, and they were found to vary con- 

 si(leral>ly in charactcT. They were classified in two general groups, one calUul Spineless diffuse, the 

 other Spineless-erect. The young plants shown above are descendants of the Spineless-diffuse 



type (F4 from the original stock of the McDonald) 

 ter; those on the right, spiny. (Fig. 11.) 



l-roiii this peculiar fruit, 1 ol:)tained 

 thirty-nine plants, in which all but one 

 showed the characters of the Logan 

 in their early >'outh; but as they were 

 all lost (luring the hrst summer, I 

 missed in this, as in many other 

 cases, the opportiMiit\- to study them 

 further. 



SUCCESSFUL RASI'HFtRRY-BLACKBERRY 

 HYMRIDIZIN'G 



I h<i<l up to this time inade frequent 

 attempts to cross the blackberries or 

 dewberries with various \arieties of 

 the raspberries, but without success, 

 until I made use of seedlings of Rubus 

 ruhrisetus (Rydb.) as i)istil plant. 



A (juart of fruit of this species was 

 obtained from southern Lotiisiana in 

 1910. The seed was sown the same 

 fall and gave rise to a large number of 

 plants, (luite uniform in general ap- 

 pearance. In 191,S, a goodly number 

 of flowers on various individtials of 

 these seedlings were poUenized with 

 the pollen from the Brilliant and 

 Loudon, red raspbcrrirs. I'rom this 



The plants on the left are spineless in charac- 



first combination with the R. ruhrisetus 

 as mother, which for short I shall call 

 the Louisiana dewberry, or still more 

 briefly the Louisiana, I raised twenty- 

 one plants to be transplanted into the 

 open field, and from the other cross 

 with the same mother and Loudon as 

 father, a few less. 



The characters of the raspberry, 

 Rubus slri^osus, were strictly dominant 

 in all the indi\iduals of each lot, nor 

 was there any discernible difference 

 in the api)earance of the two lots. 

 In both, the plants were about equally 

 infertile, though nearly all flowered at 

 the proper season. The flowers varied 

 somewhat in size on the various plants, 

 the smallest being slightly larger than 

 the raspberry, and the largest slightly 

 smaller than the Lotiisiana l)erry. 

 \\'hate\'er fruit set consisted of a few 

 drupt'lets, irregidarly ilistributed on 

 the receptacle. The color was dark-red 

 to almost brownish-black, when dead- 

 ripe. Cross pollination was attempted 

 between the various individuals, but 

 did not result in more fruit. 



