. Carnegie Institution of Washington publication. BIOTYPES AND HYBRIDS. 29 attenuate lobes, and many other variations, have behaved in many respects as if they were the normal fluctuations of a single biotype. While in cer- tain cases there appeared to be a marked capacity of one or the other ex- treme to transmit its character to its offspring", the usual result of breeding any one of these variations was a progeny giving: again the whole range of fluctuation, or a considerable portion of it. Time and again forms were picked out so different from their sibs that they were thought to repr
. Carnegie Institution of Washington publication. BIOTYPES AND HYBRIDS. 29 attenuate lobes, and many other variations, have behaved in many respects as if they were the normal fluctuations of a single biotype. While in cer- tain cases there appeared to be a marked capacity of one or the other ex- treme to transmit its character to its offspring", the usual result of breeding any one of these variations was a progeny giving: again the whole range of fluctuation, or a considerable portion of it. Time and again forms were picked out so different from their sibs that they were thought to represent distinct elementary species, but breeding-tests showed that their offspring return completely to the usual condition of the other related FIG. I'O.—Bursa bursa-pastoris rhomboidea from a family of B. bp. simplex. A half sib of the plant shown in fig. 1!). Over 100 pedigreed families, including more than 15,500 individuals derived from the two plants ( and ), have now been studied, and of these families considerably more than half ranged between forms with very obtuse lobes and others having greater or less attenuation of the lobes, the extreme developments in the latter direction being scarcely distinguish- able from pure-bred B. bp. tennis; 17 of the remaining families, in which no attenuate-lobed element was noted, had been injured by too long crowding. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Carnegie Institution of Washington. Washington, Carnegie Institution of Washington
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