History of biology

by L. C. Miall

We now resume the history of a study which down to the end of the eighteenth century had yielded only meagre and uncertain results (see above, pp. 85-88). At the date in question it had been ascertained that the spores (then called "seeds") of ferns, and probably of other cryptogams, are capable of propagating the species, but no one knew precisely what part the spore played in the life-history, or could explain the true difference between a cryptogam and a flowering plant. The great improvements in the construction of the compound microscope which were effected between 1812 and 1830 rendered it possible to elucidate much more thoroughly the structure and development of the chief groups of cryptogams. The sexual reproduction of algæ was explored; moving filaments (spermatozoids) were seen to enter the chambers in which embryos afterwards formed; the conjugation of similar cells was observed in algæ and fungi, and recognised as a simple mode of sexual reproduction. The resemblance of the spermatozoids of mosses and ferns to animal spermatozoa was noted, and their participation in the process of fertilisation was more and more closely followed until at length Hofmeister in 1851 saw them fuse with the egg-cell of a fern. Suminski, whose full name, Lesczyc-Suminski, is unpronounceable by Englishmen, had discovered (in 1848) that the prothallus of a fern, which is the product of the germinated spore and had been hitherto taken for the cotyledon, bears two kinds of reproductive organs, one of which liberates spermatozoids, while an egg-cell is developed within the other. He did not correctly describe all the details, but he showed where the essential reproductive organs form, and where fertilisation is effected. The masterly researches of Hofmeister (1849-57) fused what had been a number of partial discoveries into a connected and luminous doctrine. He proved that the prothallus is one of two generations in the life-history; that it begins with a spore and ends with a fertilised egg-cell; that in the higher cryptogams there is a regular alternation of generations; that the prothallus of the fern answers to the leafy moss, while the leafy fern is the equivalent of the moss-capsule; that the egg-cell is the same structure in both cryptogams and flowering plants; that the pollen-tube and the seed are found to-day only in flowering plants; that the gymnosperms make a transition from the higher cryptogams to the angiosperms; that unity of plan pervades the whole series of mosses, ferns, fern-like plants, gymnosperms, and angiosperms. Before Darwin's Origin of Species had appeared Hofmeister presented to evolutionists a clear example of a descent in which every principal term is well authenticated, while the extremes are far apart.

The Enrichment of English Gardens.

If some unreasonably patriotic Englishman should be seized with the whim of keeping none but truly British plants in his garden, he might enjoy the shade of the fir, yew, oak, ash, wych-elm, beech, aspen-poplar, hazel, rowan-tree, and the small willows, but he would have to forego the common elm, the larger poplars and willows, the larches, spruces, and cypresses, the rhododendrons, and all the shrubs popularly called laurels. Of fruits he might have the crab-apple, sloe, wild cherry, gooseberry, currants (black and red), the raspberry, strawberry, and blackberry, but none of the improved apples, pears, or plums, and no quinces, peaches, or apricots. His vegetable garden might yield cabbages, turnips, carrots, and celery (all deficient in size, flavour, and variety), but no cauliflowers, Brussels sprouts, parsley, lettuces, peas, beans, leeks, onions, or spinach. The handsomest of his flowers would be dog-roses, mallows, and primroses.

Before Europe was sufficiently enlightened to care about exact records valuable foreign plants had already been introduced. Vines, apples, pears, cherries, and plums, besides improved vegetables, such as the cauliflower, bean, garden-pea, and cucumber, had been brought from temperate Asia or Egypt. Wheat and barley, neither of them native to Europe, had to some extent replaced rye and oats, which may have existed naturally in those European countries which border on Asia. Britain, while yet a Roman province, shared in these benefits, and it is believed that the common elm, besides certain fruit-trees and pot-herbs, have been continuously grown in our island through all the troubled ages which separate us from the Romano-British times. Leek, garlic, and onion are ancient acquisitions. To our Old-English forefathers garlic was the spear-leek, distinguished by its long, narrow leaf from the broad-leaved common leek, just as a garfish was distinguished from other fishes by its long body and pointed head; onion was the enne- or ynne-leek (onion-leek); the most important of the three was probably that which retained the root-word without prefix—the leek proper.

During many centuries, when the rights of small proprietors were little respected and knowledge was scanty, the religious houses were distinguished by the diligence with which they tended their gardens. Flowers, fruits, and simples were cultivated, and plants were now and then imported from foreign monasteries. The English names of the plants, which are often adaptations of Latin words, still testify to the care of gardeners who were in the habit of using Latin.

Much improvement was not to be expected so long as England suffered from frequent and desolating wars within her own borders. When these at last subsided, great English gardens, such as those of Nonsuch, Hatfield, Theobalds, and Hampton Court, began to parade their beauty; strange trees, shrubs, and flowers were brought from the continent, and as early as Queen Elizabeth's time our shrubberies and walks were admired by spectators familiar with the best that Italy and France could show. The new horticulture was, however, long an exotic among us, and John Evelyn, whose Sylva appeared in 1664, was "the first to teach gardening to speak proper English."

In the latter part of the sixteenth century the following new plants among others were brought from central or southern Europe: The poppy and star anemones, the hepatica, the common garden larkspur, the winter aconite, the sweet-William, the laburnum, Rosa centifolia (of eastern origin, the parent of countless varieties and hybrids), the myrtle, the lavender, the cyclamen, the auricula, Iris germanica, and many other Irids, the oriental hyacinth, several species of Narcissus, the white and Martagon lilies, and the absurdly named dog's-tooth-violet (really a lily). The botanist Clusius introduced the jonquil and the Tazetta narcissus from Spain to the Low Countries. The Judas-tree (i.e., tree of Judæa) was brought from the Mediterranean, where the hollows of the hills are filled in April with its pale-purple blooms. The white jasmine was imported from Asia, and the castor-oil plant from Africa.

The great accessions of geographical knowledge made during the fifteenth and sixteenth centuries were slow to affect horticulture. Ships were then few and small, and the passage from Hispaniola or Calicut to Cadiz or Lisbon occupied weeks or even months. Moreover, the conquests of Spain and Portugal (Goa, the Moluccas, Brazil, the West Indies, Peru, and Mexico) lay mostly within the tropics, and could furnish hardly any plants capable of enduring a European winter. Special pains were, however, taken to bring over some valuable food-plants which were thought likely to thrive in Europe. Before any European landed in America the potato had been cultivated by the Indians of Peru, a country which, though lying almost under the line, rises into cool mountain-districts. Potato-tubers were soon introduced to Spain and Italy, and a little later to other parts of Europe; Raleigh's planting of potatoes on his estate near Cork came a few years later. The edible tomato, which is distinguished from the wild form by its enlarged fruits, was apparently cultivated in Peru before the first landing of the Spaniards. The unusually high proportion of edible plants among the first importations from America and other distant countries is worthy of remark. Early explorers eagerly sought for valuable food-plants, but the number of such as could be cultivated alive in Europe was very limited, and since the sixteenth century the attention of collectors has been fixed upon ornamental species simply because of the dearth of others.

European flower-gardens were enriched during the sixteenth century by the following American species: the so-called French and African marigolds (both from Mexico), sunflowers, the arbor-vitæ (Thuja occidentalis), Yucca gloriosa, and the Agave, misnamed the American Aloe.