. Carnegie Institution of Washington publication. MUTATIONS, VARIATIONS, AND RELATIONSHIPS OF THE OENOTHERAS. 21 It will be noted that there has been a slight fall in mean heights, but the most noteworthy thing in this comparison is the great increase in the varia- bility. A study of fig. i shows the difference in variability quite clearly in the greater amplitude and less height of the 1905 curve. The interesting fact becomes apparent that although the mean value of stem-heights in 1905 was less than that for 1904, some of the 1905 plants were taller than the tallest in 1904. The explanation
. Carnegie Institution of Washington publication. MUTATIONS, VARIATIONS, AND RELATIONSHIPS OF THE OENOTHERAS. 21 It will be noted that there has been a slight fall in mean heights, but the most noteworthy thing in this comparison is the great increase in the varia- bility. A study of fig. i shows the difference in variability quite clearly in the greater amplitude and less height of the 1905 curve. The interesting fact becomes apparent that although the mean value of stem-heights in 1905 was less than that for 1904, some of the 1905 plants were taller than the tallest in 1904. The explanation of these facts is very simple. The garden at the Station for Experimental Evolution has been under cultivation so short a 45 35 30 25 20 15 10 0. I \ —t-f 66-70 71-75 76-80 81-85 86-90 91-95 96-100 101-105 IO6-IIO FIG. 1.—Variation in height of stem of Oenothcra lam< Broken curve represents the condition at the New Vork Botanical Garden in 1904, continuous curve that at the Station for Experimental Evolution in 1905. time that it still lacks much of that homogeneity that is desirable for work of this nature. One corner of this plot of Oenothcra lamarckiana dipped into a slight depression which received the drainage from the roof of the laboratory and was therefore kept, during a portion of the growing season, too wet for the best development of the plants. A few specimens on this corner did not make flower-stems at all, and it was to be expected that those nearest this corner of the plot would be somewhat influenced by the same unfavorable conditions and made to produce flower-sterns of a slightly less altitude. The stature of Oenothcra rubrincrvis.—ln 1904 a comparison was made between the statures of Ocnothera nanella and O. lamarckiana, and it was a. 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 orig
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