February 13, 1914] 



SCIENCE 



255 



the plants he meets; by the none-too-well con- 

 cealed cynicism of our colleagues in other lines, 

 we are failing in this. Our work has been analytic, 

 not constructive. We have dismembered organisms 

 and held up to view their component parts. We 

 have been looking for differences, and with such 

 amazing success that the fundamental resem- 

 blances have, for the most part, escaped our notice. 



Morphology, physiology, ecology and economic 

 botany in its scores of applications have all gone 

 forward by leaps and bounds, but in spite of, not 

 by the aid of, taxonomy. Not all taxonomic work 

 has been useless or erroneous. Keenness of obser- 

 vation and great powers of discrimination are not 

 lacking. It is not so much that what has been 

 should not have been done, but rather that more 

 should have been done to relate recent work to 

 that which has gone before. Synthesis should have 

 followed so closely upon the analysis of the ele- 

 ments of our flora that duplications would promptly 

 have been discovered and the relation of each ele- 

 ment to the other detected and stated. 



We are on the eve of a new era of reconstruc- 

 tion. Already the pendulum is swinging back 

 toward greater conservatism. The dismember- 

 ment of genera and the multiplication of species 

 proceed more cautiously. This grows out of the 

 revitalized aim, ' ' make it easier for others to 

 know plants. ' ' 



Studies of Teratologioal Phenomena in Their Be- 

 lation to Evolution and the Problems of Hered- 

 ity: I. A Study of Certain Floral Abnormali- 

 ties in Nicotiana and Its Bearing on Theories of 

 Dominance: Orland E. White. 

 Nicotiana plants showing petalody were selfed 

 and progeny grown from them. In one race the 

 abnormal character was extremely variable, some 

 plants showing a large expression, other plants 

 showing it only to a slight degree. This race 

 varied in many other characters, proving the 

 mother plant to have been very heterozygous. In 

 another race, the abnormality was reproduced in 

 all the progeny to the same degree as in the mother 

 plant. With the exception of pollen color, no 

 variation in other characters occurred in this race, 

 indicating that it was largely homozygous in its 

 hereditary constitution. 



Pistillody originated as a discontinuous varia- 

 tion and was inherited in the same manner, 

 crosses with the normal in one case giving in F^ a 

 progeny closely approximating a simple 3: 1 

 ratio. In two hybrid Fi families, it was com- 

 pletely recessive, while in what appears to be 



another hybrid Fj family, it is wholly dominant. 

 The first two families differ from the last family 

 in a large number of characters, as the ancestry 

 of the latter involves another species. 



The catacorolla race of Nicotiana originated 

 through a discontinuous variation. Wlien crossed 

 with normal races, the Fj progeny were either in- 

 termediate in character or absolutely normal, 

 though the individual Fj progeny from each cross 

 showed no variation among themselves. Great 

 variation existed between the different pollen pa- 

 rents of many of these Fi individuals. 



As a whole, the data secured from hybridizing 

 races of normal plants with those possessing the three 

 abnormalities discussed above support the view that 

 dominance and reeessiveness are not in any way 

 attributes of the factor or ' ' character ' ' in itself, 

 but are the result of the factor expression plus the 

 modifying influence of the environment, whether 

 genotypical (all the other genetic factors of the 

 organism not primarily concerned in the trans- 

 mission of a particular character) or external (soil, 

 climate, etc.). The variability of the catacorolla 

 expression in the 119 Fi plants of ( — i — lA X 119 

 normals) is striking supporting evidence that this 

 conception of dominance is the most tenable of 

 those recently advanced by genetics. 



Observations on the Behavior of Some Species on 

 the Edges of their Ranges : Eobekt F. Griggs. 

 In the Sugar Grove region of central Ohio 

 about 125 species, 13 per cent, of the native flora, 

 reach their territorial limits. These plants are of 

 diverse geographical affinity stretching away in 

 every direction. More than half are abundant in 

 many stations; only -i^ are rare; 21 are out- 

 liers far from their next station; 27 range con- 

 tinuously up to their limits; 77 reproduce well; 

 only 18 reproduce poorly. The success of the seed- 

 lings in meeting plant competition is apparently 

 more important than success of the reproductive 

 apparatus. The theory that plants are confined 

 to their optimum habitats at their termini does 

 not accord with observation. On the contrary, 

 some plants occupy the most unfavorable habitats, 

 being forced by competition to grow where they 

 can find room. The causes of the termination of 

 these ranges is not evident. Climatic adaptability 

 is evidently the limiting factor restricting the 

 spread of species, but there does not appear to be 

 such a climatic adjustment in the present in- 

 stance, for most of these termini appear not to be 

 stable, but are either advancing or retreating. 

 There are tension zones between the different spa- 



