Mongrels and Hybrids: The Problem of "Race" in the Botanical World Vassiliki Betty Smocovitis My difficulty probably is that I do not know the exact meaning ofwords like species, speciation, populations, reproductive isolation, allopatric and sympatric speciation, geographic and ecological isolation as applied in your paper. IfI am wrong in my interpretation ofthem would you therefore kindly correct me. 1 must confess that I always have difficulties in reading papers discussing terminology, for I have in mind that the living world does not lend itself too well in our rigid classifications. I feel therefore that all kinds oftransitions exist between sympatric and allopatric distribution as well as between different kinds ofspecies. Scientific progress has often been delayed by a premature freezing ofour concepts into a terminology that hinders our clear thinking. -Jens Clausen, botanist, writing to Ernst Mayr, zoologist l The problem ofrace hasn'tfigured prominently in the entire biological world. In the plant world, for example, it rarely figures at all. What does figure, especially since Darwin first noticed it, is the deeper problem ofvariation. What it is, its origin, its maintenance and preservation (or its heritability), its pattern (continuous or discontinuous), and ultimately what biological purpose or function it serves does matter greatly. Common sense would tell us that if organisms were in fact adapted to suit their environments, then we would expect to find perfectly adopted forms, not all kinds and manners ofendless variability. The fact of the matter is that the problem of variation has been at the heart ofevolutionary thinking, yet few historians ofevolution have directly studied it. We know, for example, that Darwin drew the distinction between variation under nature and variation under domestication in much the same way that he drew the distinction between natural and artificial selection.2 We also know that he recognized its importance to his theory of descent with modification because he devoted an entire two volumes to the subject titled Variation of Animals and Plants Under Domestication. We also know that it was at the heart ofthe celebrated debate between his later intellectual supporters, the biometricians, and his detractors, the Mendelians, at the turn of the century, as well as the source of Hugo de Vries's popular mutation theory at the turn ofthe century.3 c= 81 82 ~ Vassiliki Betty Smocovitis Simply understood, the problem ofvariation was a central concern for species was problematic and that eve evolutionists after 1859.4 Questions posed included the following: What understanding even more difficult. ' was its origin? How was it maintained? What purpose did it all appear to examples, but at times they made his J serve? Why, ifadaptation were the case, did not one perfect, ideal form exist they appeared to demonstrate so m and occupy each particular zone? That question, of course, undergirded an example, Darwin was acutely a\' much of Darwin's thinking while he explored the natural history of the and how it could challenge the tidy t world during his five-year voyage aboard the HMS Beagle. Answering it for his picture of general evolutior. took more than twenty years and more than four hundred pages of text chapter-chapter 8-hedevoted spec organized by the familiar title On the Origin ofSpecies by Means ofNatural drew mostly on examples from pIa Selection, with the less familiar subtitle Or the Preservation of Favoured that denoted a cross between species Races in the Struggle for Life. denote any cross between varieties. If Darwin's famous title is an accurate indication, race was intended to issue ofhybridization in his book, n. be a category that applied to all living organisms, which in the nineteenth turn ofthe century, for example, as 1 century mostly included plants and animals. Throughout the book, Darwin to the origin ofvariation on a physiolc drew generously on examples from both the animal and the plant world, to hybridization as explaining the ( yet strangely enough, he did not in any systematic sense apply the term race the origin of new species. Explored to plants and mentioned it only rarely in the case ofanimals. Like others years 1910-1919 and 1920s or so i: before and after him, terms like variety and subspecies or species were used Hybridization, hybridization was tho instead when reference was made to the stages in plant evolution and even material that generated variation. 10 If more generally to the discernable stages of evolution. Chapter 2 ofOrigin less adapted forms. Lotsy wrote, "0 of Species, titled "Variation under Nature:' which outlines the stages in origin ofnew types, heredity perpetu; the origin of species, notes the grade from individual differences to lesser oftheir origin as was formerly suppose varieties to well-marked varieties to subspecies to species. Differences crossing and hybridization were centro between these groups "blended" into each other in an "insensible" series. at creating a natural or phylogenetic Darwin wrote, "No clear line ofdemarcation has as yet been drawn between futile. Lotsy wrote, "Phylogeny e.g. rc species and sub-species ... or, again between subspecies and well marked in the past is no science but a produc varieties, or between lesser varieties and individual differences:'5 Defining can be held but little in check by the species proved to be difficult, however, and Darwin famously skirted any incompleteness ofthe latter."12 attempt at a rigorous definition.6 He wrote, "It will be seen that I look at Lotsy himself is now regarded as the term species, as one arbitrarily given for the sake of convenience to at the turn of the century he was pa a set of individuals closely resembling each other, and that it does not people (I hesitate to call them all "bol essentially differ from the term variety, which is given to less distinct and for utilitarian ends) who rejected str more fluctuating forms:'7 (This is ironic indeed, given the book's title.) in favor of an alternative number of t It is a small wonder, then, that when Theodosius Dobzhansky turned to species. Not only did plant evolution the subject in the late 1930s, he titled his book Genetics and the Origin of hybridization and embrace theories Species. 8 It was his intention to remedy the fact that Darwin didn't properly but a large number also remained ard discuss the origin ofspecies, nor did he actually attempt to provide a true direct modification ofcharacters by tl definition. The problem of defining species remained difficult, of course, Individuals like Frederic Clements, t and indeed intractable until the 1930s. Darwin understood that it remained studying the variation patterns ofplan one ofthe weakest parts ofhis theory and noted that his understanding of the direct modification ofthe environ Mongrels and Hybrids 83 species was problematic and that evolution from the plant world made that understanding even more difficult. To Darwin, plants had made splendid examples, but at times they made his project even more complicated because they appeared to demonstrate so many special cases and anomalies. 9 As an example, Darwin was acutely aware of the problem of hybridization and how it could challenge the tidy branching patterns he tried to discern for his picture of general evolution. This much was stated in a special chapter-chapter 8-he devoted specifically to the subject ofhybrids, which drew mostly on examples from plants. For Darwin, hybrid was a term that denoted a cross between species, while the term mongrel was used to denote any cross between varieties. Darwin never properly resolved the issue of hybridization in his book, nor did many of his successors. At the turn of the century, for example, as knowledge of genetics drew attention to the origin ofvariation on a physiological level, botanists turned seriously to hybridization as explaining the origin of variation and, thenceforth, the origin of new species. Explored by individuals like J. P. Lotsy in the years 1910-1919 and 1920s or so in books like Evolution by Means of Hybridization, hybridization was thought to be the specific source of raw material that generated variation. to Ifselection acted, it was to cull out the less adapted forms. Lotsy wrote, "Crossing therefore is the cause of the origin ofnew types, heredity perpetuates them, selection is the cause-not of their origin as was formerly supposed-but oftheir extinction:'11 Because crossing and hybridization were central evolutionary processes, any attempt at creating a natural or phylogenetic method in taxonomy was therefore futile. Lotsy wrote, "Phylogeny e.g. reconstruction of what has happened in the past is no science but a product of phantastical speculations which can be held but little in check by the geological record, on account of the incompleteness of the latter:'ll Lotsy himself is now regarded as a marginal and obscure figure, but at the turn of the century he was part of a large community of "planty" people (I hesitate to call them all "botanists" since many only used plants for utilitarian ends) who rejected strict notions of Darwinian evolution in favor of an alternative number of theories to account for the origin of species. Not only did plant evolutionists espouse evolution by means of hybridization and embrace theories like de Vries ian Mutationstheorie, but a large number also remained ardent neo-Lamarckians, accepting the direct modification of characters by the environment, well into the 1930s. Individuals like Frederic Clements, the celebrated ecologist, and others studying the variation patterns ofplants in nature saw what appeared to be the direct modification ofthe environment on plant characters. 84 Vassiliki Betty Smocovitis The Biological Attributes of Plants environmental shifts. (Good exan What was it that made plant evolution so intractable? While they were the between sun and shade leaves on preferred study or model organism (to use a modern term) for a number shape ofplants submerged and th ofevolutionists and especially geneticists in the early years ofthe twentieth environments or exposed to air).