The group of late fifteenth-century herbals which we discussed in Chapter II—the Latin and German Herbarius and the Hortus Sanitatis—are alike in giving very brief and inadequate accounts of the characters of the plants enumerated, although their descriptions often have a certain naïve charm. It is scarcely worth while to give actual examples of their methods. It will perhaps suffice to quote a few specimens from the English ‘Grete Herball25,’ which is a work of much the same class. The Wood Sorrel26 is dealt with as follows: “This herbe groweth in thre places, and specyally in hedges, woodes and under walles sydes and hath leves lyke iii leved grasse and hath a soure smell as sorell, and hath a yelowe flowre.” As another example we may cite the Chicory, which is described as having “croked and wrythen stalkes, and the floure is of y^e colour of the skye.” Of the Waterlilies, we receive a still more generalised account: “Nenufar is an herbe that groweth in water, and hath large leves and hath a floure in maner of a rose, the rote thereof is called treumyan and is very bygge. It is of two maners. One is whyte, and another yelowe.” Occasionally we meet with a hint of more detailed observation. For instance, the coloured central flower in the umbel of the Carrot is mentioned, though in terms that sound somewhat strange to the modern botanist. We read that it “hath a large floure and in the myddle therof a lytell reed prycke.”

It is somewhat remarkable that Banckes’ Herbal, though originally published a year earlier than the first edition of the Grete Herball, shows a slight but distinct superiority in the matter of description (see p. 38). Perhaps this is to be connected with the fact that Banckes’ Herbal is without illustrations. But even if we allow that the descriptions in Banckes’ Herbal occasionally seize on salient features, it must be admitted that they still leave a great deal to the imagination. As two typical examples, which are perhaps as good as any in the book, we may take those of Tutsan27 and of Shepherd’s Purse. Of the first the herbalist writes, “This herbe hathe leves somdele reed lyke unto ye leves of Orage. And this herbe hathe senowes on his leves as hath Plantayne, and it hathe yelowe floures and bereth blacke berys, and it groweth in dry woodes.” Of Shepherd’s Purse he says, “This herbe hathe a small stalke and full of braunches and ragged leves and a whyte flowre. The coddes therof be lyke a purse.”

The ‘Herbarum vivæ eicones’ of Otto Brunfels (1530) was the first herbal illustrated with drawings, which are throughout both beautiful and true to nature. The descriptions, on the other hand, are quite unworthy of the figures, being mostly borrowed from earlier writers. The wonderful excellence of the wood-blocks, with which the German Fathers of Botany enriched their books, was, in one sense, an actual hindrance to the development of the art of plant description. Since the pencil of the draughtsman could represent every subtlety in the characteristic form of a plant, the botanist might well be excused for thinking that to take the trouble to set beside the drawing a precise, verbal description of the plant in question was a work of supererogation. However, in another sense the draughtsman indirectly helped the cause of scientific accuracy in what, for want of a better expression, may be called word-painting. There is no doubt that constant critical examination of the artist’s work must have tended to educate the eye of the botanist who supervised his efforts, and to increase his perception of delicate shades of difference or similarity of form, which he might never have noticed, or attempted to express in words, if the draughtsman had not, as it were, lent him his trained eyesight.

The next great worker, Hieronymus Bock, differs from Brunfels in the comparative unimportance of his contributions to plant illustration, and the relatively greater value of his text. His descriptions of flowers and fruits are excellent, and the way in which he indicates the general habit is often masterly. As an example we may quote his description of Mistletoe plants, which may be translated as follows: “They grow almost in the shape of a cluster, with many forks and articulations. The whole plant is light green, the leaves are fleshy, plump and thick, larger than those of the Box. They flower in the beginning of spring, the flowers are however very small and yellow in colour, from them develop, towards autumn, small, round white berries very like those on the wild gooseberry. These berries are full inside of white tough lime, yet each berry has its small black grain, as if it were the seed, which however does not grow when sown, for, as I have said above, the Mistletoe only originates and develops on trees. In winter mistel thrushes seek their food from the Mistletoe, but in summer they are caught with it, for bird-lime is commonly made from its bark. Thus the Mistletoes are both beneficial and harmful to birds.”

In ‘De historia stirpium,’ the great Latin work of Leonhard Fuchs, the plant descriptions are brief and of little importance, being frequently taken word for word from previous writers. This book, however, is notable in possessing a full glossary of the technical terms used, which is of importance as being the first contribution of the kind to botanical literature. We may translate two examples at random, to show the style of Fuchs’ definitions:—

“Stamens are the points [apices] that shoot forth in the middle of the flower-cup [calyx]: so called because they spring out like threads from the inmost bosom of the flower28.”

“Pappus, both to the Greeks and to the Latins, is the fluff which falls from flowers or fruits. So also certain woolly hairs which remain on certain plants when they lose their flowers, and afterwards disappear into the air, are pappi, as happens in Senecio, Sonchus and several others.”

In the German edition of Fuchs’ herbal, the descriptions are remarkably good for their time, being more methodical than those of Bock, though sometimes less lively and picturesque. As an instance of his manner we may cite his account of the Butterbur, of which his wood-cut is shown in Text-fig. 58. “The flower of Butterbur,” he writes, “is the first to appear, before the plant or leaves. The flower is cluster-shaped, with many small, pale pinkish flowerets, and is like a fine bunch of vine flowers in full bloom to look at. This large cluster-shaped flower has a hollow stalk, at times a span high; it withers and decays without fruit together with the stalk. Then the round, gray, ash-coloured leaves appear, which are at first like Coltsfoot, but afterwards become so large that one leaf will cover a small, round table. They are light green on one side, and whitish or gray on the other. Each leaf has its own brown, hairy and hollow stem, on which it sits like a wide hat or a mushroom turned over. The root grows very thick, is white and porous inside, and has a strong, bitter taste.”

Our English herbalist, William Turner, is often fresh and effective in his descriptions. He compares the Dodder (Cuscuta) to “a great red harpe strynge,” and the seed vessels of Shepherd’s Purse to “a boyes satchel or litle bagge.” Of the Dead Nettle he says, “Lamium hath leaves like unto a Nettel, but lesse indented about, and whyter. The downy thynges that are in it like pryckes, byte not, ye stalk is four-square, the floures are whyte, and have a stronge savor, and are very like unto litle coules, or hoodes that stand over bare heades. The sede is blak and groweth about the stalk, certayn places goyng betwene, as we se in horehound.”

The three great botanists of the Low Countries, Dodoens, de l’Écluse and de l’Obel, were so closely associated that it is hardly necessary to consider their style of plant description individually. Henry Lyte’s well-known herbal of 1578 was a translation of the ‘Histoire des Plantes,’ which is itself a version by de l’Écluse of the Dutch herbal of Dodoens. We may thus fairly illustrate the style of plant description of this school by a quotation from Lyte, since it has the advantage of retaining the sixteenth-century flavour, which is so easily lost in a modern translation. As a typical example we may take a paragraph about the Storksbill (Erodium). It will be noticed that it does not represent any great advance upon Fuchs’ work.

“The first kinde of Geranion or Storckes bill, his leaves are cut and iagged in many peeces, like to Crowfoote, his stalkes be slender, and parted into sundry braunches, upon which groweth smal floures somwhat like roses, or the floures of Mallowes, of a light murrey or redde colour: after them commeth little round heades, with smal long billes, like Nedels, or like the beakes of Cranes and Hearons, wherein the seede is contayned: The roote is thicke, round, shorte, and knobby, with certayne small strings hanging by it.”

In his ‘Pemptades’ of 1583, Dodoens gave a glossary of botanical terms. His definitions suffer, however, from vagueness, and are not calculated greatly to advance the accurate description of plants. As an example we may take his account of the flower, which may be translated as follows:—

“The flower (ἄνθος) we call the joy of trees and plants. It is the hope of fruits to come, for every growing thing, according to its nature, produces offspring and fruit after the flower. But flowers have their own special parts.”

The descriptions from the pen of de l’Écluse are characterised by greater fulness and closer attention to flower structure than those of his predecessors. The plant which he calls Sedum or Sempervivum majus, of which his wood-cut is reproduced in Text-fig. 59, is described as being “a shrub rather than a herb; occasionally it reaches the height of two cubits [3 ft.] and is as thick as the human arm, with a quantity of twigs as thick as a man’s thumb: these spread out into numerous rays of the thickness of a finger. The ends of these terminate in a kind of circle, which is formed by numerous leaves pressing inwards all together and overlapping, just as in Sedum vulgare majus. These leaves however are fat and full of juice, and shaped like a tongue, and slightly serrated round the edge, with a somewhat astringent flavour; the whole shrub is coated with a thick, fleshy, sappy bark. The outer membrane inclines to a dark colour, and is speckled as in Tithymalus characia: the speckles are simply the remains of leaves which have fallen off. Meanwhile a thick pedicel covered with leaves springs out from the top of the larger branches, and bears, so to speak, a thyrsus of many yellow flowers, scattered about like stars, pleasant to behold. And when the flowers begin to ripen, and are running to seed (the seed is very small), the pedicel grows slender. But the plant is an evergreen.”

In Gerard’s ‘Herball’ of 1597 the descriptions are seldom sufficiently original to be of much interest. We may quote, however, his account of the Potato flower (Text-fig. 60), then so great a novelty that in his portrait (Plate XII) he is represented holding a spray of it in his hand. It has, he says, “very faire and pleasant flowers, made of one entire whole leafe, which is folded or plaited in such strange sort, that it seemeth to be a flower made of sixe sundrie small leaves, which cannot be easily perceived, except the same be pulled open. The colour whereof it is hard to expresse. The whole flower is of a light purple color, stripped down the middle of every folde or welt, with a light shew of yellownes, as though purple and yellow were mixed togither: in the middle of the flower thrusteth foorth a thicke fat pointell, yellow as golde, with a small sharpe greene pricke or point in the middest thereof.”

The plant descriptions by Valerius Cordus, which were published after his death, are among the best produced in the sixteenth century, but they are too lengthy for quotation here.

So far as the period with which we deal in this book is concerned, the zenith of plant description may be said to be reached in the ‘Prodromos’ of Gaspard Bauhin (1620), in which a high level of terseness and accuracy is attained. As an example we may translate his description of “Beta Cretica semine aculeato,” of which his drawing is reproduced in Text-fig. 62: “From a short tapering root, by no means fibrous, spring several stalks about 18 inches long: they straggle over the ground, and are cylindrical in shape and furrowed, becoming gradually white near the root with a slight coating of down, and spreading out into little sprays. The plant has but few leaves, similar to those of Beta nigra, except that they are smaller, and supplied with long petioles. The flowers are small, and of a greenish yellow. The fruits one can see growing in large numbers close by the root, and from that point they spread along the stalk, at almost every leaf. They are rough and tubercled and separate into three reflexed points. In their cavity, one grain of the shape of an Adonis seed is contained; it is slightly rounded and ends in a point, and is covered with a double layer of reddish membrane, the inner one enclosing a white, farinaceous core.”

Any great advance on Bauhin’s descriptions could hardly be expected during the period which we are discussing, since it closed before the nature of the essential parts of the flower was really understood. It was not until 1682 that the fact that the stamens are male organs was pointed out in print by Nehemiah Grew, though he himself attributed this discovery to Sir Thomas Millington, a botanist otherwise unknown. Gerard’s account of the stamens and stigma of the Potato as a “pointell, yellow as golde, with a small sharpe greene pricke or point in the middest thereof,” vague as it seems to the twentieth-century botanist, is by no means to be despised, when we remember that the writer was handicapped by complete ignorance of the function of the structures which he saw before him.

A further hindrance to improvement in plant description was the lack of a methodical terminology. As we have already shown, both Fuchs and Dodoens attempted glossaries of botanical terms, but these do not seem to have become an integral part of the science. It is a common complaint among non-botanists at the present day, that the subject has become incomprehensible to the layman, owing to the excessive use of technical words. There is, no doubt, some truth in this statement, but, on the other hand, a study of the writings of the earlier botanists makes it clear that a description of a plant couched in ordinary language—in which the botanical meaning of the terms employed has been subjected to no rigid definition—often breaks down completely on all critical points.

It is to Joachim Jung and to Linnæus that we owe the foundations of the accurate terminology, now at the disposal of the botanist when he sets out to describe a new plant. The published work of these two writers belongs, however, to the late seventeenth and eighteenth centuries, and is thus outside the scope of the present volume.

CHAPTER VI
THE EVOLUTION OF PLANT CLASSIFICATION

IN the earliest European works on natural history—those of the Aristotelian school—we meet with an attempt to classify the different varieties of plants. It was inevitable that the writers of this school should make such an attempt, since no mind trained in Greek philosophy could be content to leave a science in the condition of a mere chaos of isolated descriptions. At first the most obvious distinction, that of size, was used as the chief criterion whereby to separate the different groups of the vegetable kingdom. In the ‘History of Plants’ of Theophrastus, we find Trees, Shrubs, Bushes and Herbs treated as definite classes, within which, cultivated and wild plants are distinguished. Other distinctions of lower value are made between evergreen and deciduous, fruiting and fruitless, and flowering and flowerless plants.

Albertus Magnus, who kept alive in the Middle Ages the spirit of Aristotelian botany, was more advanced than Theophrastus in his method of classification. It is true that he divides the vegetable world into Trees, Shrubs, Undershrubs, Bushes, Herbs and Fungi, but at the same time he points out that this is an arbitrary scheme, since these groups cannot always be distinguished from one another, and also because the same plant may belong to different classes at different periods of its life. A study of the writings of Albertus reveals the fact that he had in mind, though he did not clearly state it, a much more highly evolved system, which may be diagrammatically represented as follows. The modern equivalents of his different groups are shown in square brackets:—

The word tunicate in the above table is used for the plants which Albertus describes as growing “ex ligneis tunicis.” It seems clear from this expression that he realised that there was an anatomical distinction between Dicotyledons and Monocotyledons.

Considering how much Albertus had achieved, it is somewhat curious that Cesalpino, who represented Aristotelian botany in the sixteenth, as Albertus did in the thirteenth century, should have produced so inadequate a system as his own contribution to the subject. We owe to him one marked advance, the recognition, namely, of the importance of the seed. On the whole, however, his classification savours too much of having been thought out in the study, and it suffers by comparison with other systems of about the same period, such as those of de l’Obel and Bauhin, which were arrived at rather by instinct, acting upon observation, than by a definite and self-conscious intellectual effort.

Cesalpino makes his main distinction, on the old Aristotelian plan, between Trees and Shrubs on the one hand, and Undershrubs and Herbs on the other. He divides the first of these groups into two, and the second into thirteen classes, depending chiefly on seed and fruit characters. Very few of these classes really represent natural groups, and the chief of all distinctions among Flowering Plants, that between Dicotyledons and Monocotyledons, which was foreshadowed by Albertus, is almost lost to sight.

When we turn from the botanical philosophers to the herbalists proper, we find an altogether different state of affairs. The Aristotelian botanists were conscious, from the beginning, of the philosophic necessity for some form of classification. The medical botanists, on the other hand, were only interested in plants as individuals, and were driven to classify them merely because some sort of arrangement was necessary for convenience in dealing with a large number of kinds. The first Materia Medica, that of Dioscorides, shows some attempt at order, but the arrangement is seldom at all natural. Occasionally the author groups together plants which are nearly related, as when he treats of a number of Labiates, or of Umbellifers successively—but this is rare.

Pliny was not, strictly speaking, a medical botanist, but at the same time he may be mentioned in this connection, since his interest in plants was essentially utilitarian. Like Theophrastus, he begins his account of plants with the trees, but his reason for so doing is profoundly different from that of the Greek writer, and illustrates the divergence between what we may call the anthropocentric and the scientific outlook upon the plant world. Theophrastus placed trees at the head of the vegetable kingdom, because he considered their organisation the highest, and most completely expressive of plant nature; Pliny, on the other hand, began with trees because of their great value and importance to man. As an example of his ideas of arrangement, we may mention that he places the Myrtle and Laurel side by side, because the Laurel takes a corresponding place in triumphs to that accorded to the Myrtle in ovations!

Turning to the herbals themselves, we find that the earliest show no trace of a natural grouping, the plants being, as a rule, arranged alphabetically. This is the case, for instance, in the Latin and German Herbarius, the Ortus Sanitatis and their derivatives, and even in the herbals of Brunfels and of Fuchs in the sixteenth century. In Bock’s herbal, on the other hand, the plants are grouped as herbs, shrubs and trees, according to the classical scheme. The author evidently made some effort, within these classes, to arrange them according to their relationships. In the preface to the third edition he writes—“I have placed together, yet kept distinct, all plants which are related and connected, or otherwise resemble one another and are compared, and have given up the former old rule or arrangement according to the A.B.C. which is seen in the old herbals. For the arrangement of plants by the A.B.C. occasions much disparity and error.”

Although the larger classificatory divisions, as now understood, were not recognised by these early workers, they had at least a dim understanding of the distinction between genera and species. This dates back to Theophrastus, who showed, by grouping together different species of oaks, figs, etc., that he had some conception of a genus. We owe to Konrad Gesner the first formulation of the idea that genera should be denoted by substantive names. He was probably the earliest botanist who clearly expounded the distinction between a genus and a species. In one of his letters he writes—“And we may hold this for certain, that there are scarcely any plants that constitute a genus which may not be divided into two or more species. The ancients describe one species of Gentian; I know of ten or more.”

Very little of Gesner’s botanical work was ever published, and it was left to Fabio Colonna to put before the botanical world the true nature of genera. He held most enlightened views on the subject, and, in 1616, clearly stated in his ‘Ekphrasis’ that genera should not be based on similarities of leaf form, since the affinities of plants are indicated not by the leaf, but by the characters of the flower, the receptacle, and, especially, the seed29. He brought forward instances to show that previous authors had sometimes placed a plant in the wrong genus, because they only attended to the leaves and ignored the structure of the flower.

however, really essential. In the preface to the ‘Phytopinax’ (1596) Bauhin states that, for the sake of clearness, he has applied one name to each plant and added also some easily recognisable character30.

The binomial method was foreshadowed at a very early date, for in a fifteenth-century manuscript of the old herbal ‘Circa instans,’ to which we have referred on p. 24, this system prevails to a remarkable extent.

When we turn to those general schemes of classification which were evolved by the herbalists of the sixteenth century, we are at once struck by the great difference existing between the principles on which these schemes are based, and those at which we have arrived at the present day. To classify plants according to their uses and medicinal properties is obviously the first suggestion that arises, when the universe is regarded from a simple, anthropocentric standpoint. In the Grete Herball of 1526 we get a ludicrously clear example of this method, applied to the special case of the Fungi. “Fungi ben mussherons.... There be two maners of them, one maner is deedly and sleeth [slayeth] them that eateth of them and be called tode stoles, and the other dooth not.” This account of the Fungi occurs also in the earlier manuscript herbal, ‘Circa instans,’ mentioned in the last paragraph.

This theory of classification has been shown in more recent times to contain the germ of something more nearly approaching a natural system than one would imagine at first sight. Both Linnæus and de Jussieu have pointed out that related plants have similar properties, and, in 1804, A. P. de Candolle, in his ‘Essai sur les propriétés médicales des Plantes, comparées avec leurs formes extérieures et leur classification naturelle,’ carried the argument much further. He showed that in no less than twenty-one families of flowering plants, the same medicinal properties were found throughout all the members of the order. This is very remarkable, when we remember that the state of knowledge at that time was such that de Candolle was obliged to dismiss a large number of orders with the words “properties unknown.” Quite recently the subject of the differentiation of groups of plants according to their chemistry has again come to the fore, and, in the future, chemical characters will probably be numbered among the recognised criteria for use in elaborating schemes of classification.

In the history of botanical classification, the first advance from the purely utilitarian standpoint was marked by the recognition of the fact that the structure and mode of life of the plants themselves are of importance. In the work of writers such as Dodoens and d’Aléchamps, to take two typical examples, we find the issues curiously confused by the working of three different principles side by side; that is to say, by the simultaneous insistence (i) on the habitat, (ii) on the “virtues,” and (iii) on the structure, as affording clues to the systematic position of the plant in question. The herbalist thus erects his scheme on a basis consisting of a confused medley of ecological, medical, and morphological principles. An enumeration of the eighteen headings, under which d’Aléchamps, in 1586, described the vegetable kingdom, so far as it was then known, will show the perplexities which surrounded the first gropings after a natural system. His headings may be translated as follows:—

Among these eighteen groups, the only ones which have any pretension to being natural are VI (Umbellifers) and XIV (Thistles), and these merely approximate roughly to related groups of genera. Among the Umbellifers we meet with Achillea and other genera which do not really belong to the order, whilst, with the Thistles, there are grouped other spiny plants, such as Astragalus tragacantha, which, in a natural system, would occupy a place remote from the Composites.

In the first book of Dodoens’ ‘Pemptades’ (1583) the principles of botany are discussed. The old Aristotelian classification into Trees, Shrubs, Undershrubs and Herbs is accepted, but with some reservations. The author points out that an individual plant may, owing to cultivation, or from some other cause, pass from one class into another. He instances Ricinus, which is an herbaceous annual with us, but a tree in other countries31.

The general scheme of classification, which Dodoens propounded, has much in common with that of d’Aléchamps, which we have already outlined. Within the larger groups, he shows a stronger perception of natural grouping than appears in his arrangement of the larger classes themselves. He often grouped together genera which we now regard as members of the same natural order, and species which we now look upon as belonging to a single genus. For instance he brought together genera belonging respectively to the Geraniaceæ, Hypericaceæ, Plantaginaceæ, Cruciferæ, Compositæ, etc. In some cases, however, he was only partially successful, as in the Umbelliferæ, among which he described Nigella (Love-in-a-Mist) and a couple of Saxifrages. This example shows how little stress was laid on the flowers and fruit at this time, from the point of view of classification. The general habit, and the shape of the leaves were the features that received most attention.

Resemblances and differences between the forms of the leaves alone must naturally appear to the botanist of the present day to be a very inadequate basis for a general system of classification. Nevertheless Mathias de l’Obel worked out a scheme on these lines which had great merit, and was a considerable advance on previous efforts. He put forward his system in his ‘Stirpium adversaria’ (1570-71) and used it also in his later work. It was thus published much earlier than the very primitive schemes of d’Aléchamps and Dodoens to which we have just referred. The best point of his system is that, by reason of their characteristic differences of leaf structure, he distinguishes the classes now known to us as Monocotyledons and Dicotyledons. He introduces a useful feature in the shape of a synoptic table of species which precedes each more or less natural group of plants. The superiority of his classification to the other arrangements in the field at the time was immediately realised. We have evidence of this in the fact that, after his ‘Kruydtbœck’ was published, Plantin brought out an album of the wood-engravings used in the book, which, although they had also appeared as illustrations to the works of Dodoens and de l’Écluse, were now arranged as in the scheme put forward by de l’Obel, “according to their genus and mutual relationship32.”

There seems little doubt that de l’Obel made a more conscious effort than any of his predecessors to arrive at a natural classification, and that he realised that such a classification would reveal a unity in all living beings. In the preface to his ‘Stirpium adversaria nova’ of 1570 he writes—“For thus in an order, than which nothing more beautiful exists in the heavens or in the mind of a wise man, things which are far and widely different become, as it were, one thing.”

De l’Obel’s scheme is not expressed in the clear manner to which we have become accustomed in more modern systems, because, in common with other botanists of his time, he did not, as a rule, give names to the groups which we now call orders, or draw any sharp line of distinction between them.

De l’Obel’s arrangement, in spite of its good features, had serious drawbacks. The anomalous Monocotyledons, such as Arum, Tamus, Aloe and Ruscus, are scattered among the Dicotyledons, while Drosera (the Sundew) appears among the Ferns, and so on. Similarities of leaf form, which are now regarded merely as instances of “homoplastic convergence,” are responsible for many curious groupings. For instance in the ‘Kruydtbœck’ we find the Twayblade (Listera) the May Lily (Maianthemum) and the Plantain (Plantago) described in succession, while, in another part of the book, various Clovers (Trifolium), Wood Sorrel (Oxalis) and Anemone hepatica are grouped together. It is also not surprising that the Marsh Marigold (Caltha), the Waterlilies (Nymphæa and Nuphar), Limnanthemum and Frogbit (Hydrocharis) should follow one another, or that de l’Obel should have brought together the Broomrape (Orobanche), the Toothwort (Lathræa), the Bird’s-nest Orchid (Neottia) and a number of Fungi. In these latter instances the author has really arrived at genuine biological (though not morphological) groups. He has recognised, on the one hand, the marked uniformity of the type of leaf characteristic of “swimming” water-plants, and, on the other hand, he has observed the leaflessness and absence of green colour, which are negative features common to so many saprophytes and parasites.

The perception of natural affinities among plants which, in the sixteenth and seventeenth centuries, was gradually, in a dim, instinctive fashion, arising in men’s minds, is perhaps best expressed in the work of Gaspard Bauhin, especially in his ‘Pinax theatri botanici’ (1623). This work is divided into twelve books, each book being further sub-divided into sections, comprehending a variable number of genera. Neither the books nor the sections have, as a rule, any general heading, but there are certain exceptions. For instance, Book II is called ‘de Bulbosis,’ and a section of Book IV, including eighteen genera, is headed ‘Umbelliferæ.’ Some of the sections represent truly natural groups. Book III, Section VI, for example, consists of ten genera of Compositæ, while Book III, Section II includes six Crucifers. Other sections contain plants of more than one family, but yet show a distinct feeling for relationship. For instance, Book V, Section I includes Solanum, Mandragora, Hyoscyamus, Nicotiana, Papaver, Hypecoum and Argemone—that is to say four genera from the Solanaceæ followed by three from the Papaveraceæ. The common character which brings them together here is, no doubt, their narcotic property, but, although no definite line was drawn between the plants belonging to these two widely sundered families, the order in which they are described shows that their distinctness was recognised. Some of Bauhin’s other groups, however, which, like that just discussed, are distinguished by their properties, or, in other words, by their chemical features, have no pretension to naturalness from a morphological standpoint. This is the case with the group described in Book XI, Section III under the name of “Aromata,” which consists of a heterogeneous assemblage of genera belonging to different orders, which are only connected by the fact that they all yield spices useful to man.

There is no doubt that, on the whole, Bauhin was markedly successful in recognising affinities within small cycles, but he broke down on the broader question of the relationships between the groups of genera so constituted. This is, however, hardly surprising when we remember how much difference of opinion exists among systematic botanists, even to-day, upon the subject of the relations of the orders to one another.

Like de l’Obel, Bauhin seems to have believed in the general principle of a progression from the simpler to the more highly developed forms. His application of this principle led him to begin with the Grasses and to conclude with the Trees. The question as to which groups among the Flowering Plants [Angiosperms] are to be considered as relatively primitive, is still, at the present day, an open one, but it would be generally conceded that Bauhin’s arrangement cannot be accepted. There is little doubt, from the standpoint of modern botany, that the Grasses are a highly specialised group, while the “tree habit” has been adopted independently by many plants belonging to entirely different cycles of affinity, and thus, except in rare cases, it cannot be used as a criterion of relationship.

On the subject of the relations of the Cryptogams (flowerless plants) to the Phanerogams (flowering plants), Bauhin had evidently no clear ideas, but such could hardly be hoped for in the state of knowledge of that time. We find, for instance, the Ferns, Mosses, Corals(!), Fungi, Algæ, the Sundew, etc., sandwiched between some Leguminosæ, and a section consisting chiefly of Thistles.

The classification put forward by the Bohemian botanist, Zaluziansky, in 1592, although in its general features no better than that of Dodoens, or of d’Aléchamps, and certainly less satisfactory than that of de l’Obel or the later scheme of Bauhin, is an improvement on all of these in one particular, namely, that he begins with the Fungi and deals next with Mosses. After the Mosses he describes the Grasses, and his classification concludes with the Trees. He was thus evidently attempting to pass from the simpler to the more complex, and his arrangement indicates that, unlike certain other botanists of his time, he looked upon the Lower Cryptogams as comparatively simple and primitive plants. He was not so clear-sighted, however, on the subject of the Ferns, for he placed them with the Umbelliferæ and some Compositæ, no doubt because he was influenced by the form of the leaf.