Plant-breeding; comments on the experiments of Nilsson and Burbank . l three in the same way. They con-stituted a new type which has been called OEnothera lata orthe broad-leaved evening primrose. Its leaves have roundedtips, its stems are weak and bencUng and scarcely reach halfthe size of those of Lamarcks primrose. It has thick flower-buds and produces flowers the petals of which often cannotcompletely flatten themselves. The anthers are barren ofpollen, dry and twisted. Its ovary, however, is normal andcan easily be fertiUzed by the pollen of the parent doing so the next generat
Plant-breeding; comments on the experiments of Nilsson and Burbank . l three in the same way. They con-stituted a new type which has been called OEnothera lata orthe broad-leaved evening primrose. Its leaves have roundedtips, its stems are weak and bencUng and scarcely reach halfthe size of those of Lamarcks primrose. It has thick flower-buds and produces flowers the petals of which often cannotcompletely flatten themselves. The anthers are barren ofpollen, dry and twisted. Its ovary, however, is normal andcan easily be fertiUzed by the pollen of the parent doing so the next generation is, of course, of hybrid origin,but it does not produce intermediates but consists of sometypical CEnothera lata and some normal Qlnotheni Lamarck-iana. By repeating the cross the lata type maybe kept indefi-nitely, occurring in about the same numerical proportionin each generation. Starting from these mutations, I began a regular scientiflcpedigree culture of Lamarcks evening primrose, fertilizingthe flowers artificially with their own pollen, protecting them. Fig. 7. IMutants of the Evening-primrose. A. Thered-veined form (O. riibrinervis), which is of the samesize as the original species. B and C. The dwarfishvariety {Oen. nuuella). 22 PLANT-BREEDING from the visits of insects by paper bags and sowing, eachyear, the seeds of some few normal individuals of the raceTliis pedigree embraces, now, about a dozen generations,the first few of which were biennial, but the later tliis stock of normal plants it has regularly repeated itsfirst mutation, producing some latas in almost every genera-tion. The number of these mutants was, on the average,about i^ per cent, the mutants themselves being always alike. Moreover, my pedigree culture has produced quite anumber of other mutants. The most frec|uent among themis a dwarfish variety, the first flowers of which open when thestem is only some few inches high. It is called CEnothcrananella and occurs as frecpiently as the
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