The Classification of PlantsAuthor(s): S. A. BennettSource: The Irish Naturalists' Journal, Vol. 1, No. 1 (Sep., 1925), pp. 6-8Published by: Irish Naturalists' Journal Ltd.Stable URL: http://www.jstor.org/stable/25531121 .

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6 Thij; Irish Naturalists' Journal. [V?l- !

BOTANICAL EDITORIAL. The subject of Botany is such a vast one, with so many

ramifications, many of them of recent growth, that it may be as

well, in this our first number, to indicate briefly those aspects of it to which this journal will devote most of its attention.

Our aim will be "to collect and disseminate knowledge of our Irish plants considered as living entities; their microscopic struc ture and obscure questions of plant physiology will be treated of only in so far as they further this intention, the point of view

adopted being that of the student of Nature rather than that of the academic botanist.

Obviously then, a task which has immediate claim on our

space is tKat of providing the means wherebv any one of our

plants may be readily and accurately identified, and with this end in view two articles will be found in this number, one by Mr.

Bennett, in which a rough outline of the sub-divisions of the botanical kingdom is attempted, and one by Ca.pt. Chase, on the identification of our local Buttercups.

We hope from time to time to give space to contributions in which plant life is discussed in its relaBon to human life and

knowledge. Our field crops, the weeds of cultivation, the hordes of immigrant alien plants which are continually landed on our

shores, the life-histories and the uses (medical or otherwise) of our

plants, and the extensive and interesting folk-lore associated with

many of them, together with the ever-recurring problems of the farmer, the gardener and the plant-breeder, are all subjects which

call for treatment in these columns. Those of our readers who

are engaged in the teaching of Nature Study in our schools should find abundant material ready to their hand. S. A. B.

W. R. M.

THE CLASSIFICATION OF PLANTS.

By S. A. Bennett, B.A., B.Sc.

A natural system of plant classification will take no account of where a plant growTs, or what its use may happen to be at any

particular time or place to any group of people, but should be based simply on the general affinities of the plants themselves, so that like may go with like. In this way the real relationships

which obtain among our present-day plants, in virtue of their

descent during geological time from earlier and more primitive plants, will be the more clearly expressed, and we shall be in a

position to co-ordinate a mass of very miscellaneous knowledge as it becomes available to us through the researches of the academic botanist

The degree of affinity or relationship between the members of a family of plants is settled by the number and importance in

the life-history of the plants, of the characters which thev

have in common, and obviously the big divisions of the vegetable

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September, 1925.] 7

kingdom include almost innumerable variations within their boundaries, and the plants grouped within them have but few characters in common.

These big divisions?there are four of them?are known as

the PHYLA of the plant-world.

They are as follows : ?

(a) The Thallophyta, which have no root, stem or leaves; they include plants like the algae (sea-weeds) and the fungi (mushrooms, moulds and rusts).

(b) The Bryophyta or mosses.

(c) The Pteridophyta or ferns, and

(d) The Spermophyta or seed-producing plants. All these four Phyla are further divided and sub-divided into

Classes, Sub-Classes, Groups and Natural Orders, and these

Natural Orders are again divided into Genera and Species. Each division and sub-division is based ou one or more characters which

the plants in it have in common, ruling out those which do not

happen to possess this distinguishing character.

The consequence of all this is that the placing of a plant correctly into its Genus and Species becomes an epitome of all our knowledge of the plant, which has been rendered available

by the labours of previous workers in the same field, and as a

further consequence it follows that the correct naming of a plant is well worth while.

It should, however, be mentioned that up to the present day the different systems that have come into vogue at different times have been based on structural similarities without reference to

physiological resemblances, so that even the modern method of classification may not yet be perfect in all its details. There is, of course, an obvious and intimate connection between the

physiology, that is to say the life processes of the plant, and its

structure, and accordingly we may take it that the main outlines of the present system of classification are scientifically correct, and fairly represent the state of affairs in the vegetable kingdom as we find it.

Take as an example the Buttercups, which are discussed in

another article in this number. They resemble one another in

many points which they have in common with one another and with no other flowers; these points of resemblance put them into the Genus

" Ranunculus." But there are other flowering plants,

e.g., the Anemones, which more or less resemble the Buttercups; there are in fact something like 27 different groups of plants whose general build, shall we say, is sufficiently like that of the

Buttercups to ensure that they shall all go into the some com

partment. This is what is meant by a *'

Natural Order/' and this Natural Order has received the name of

" Ranunculaceae,"

being in fact named after the most important Genus, "

Ranun culus

" (the Buttercups), which it contains,

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8 The Irish Naturalists* Journal. [Vol. 1.

We may put the matter another way. Taking the world over, we find that there is a big group of

plants which all resemble one another in the following points: ?

" They are herbs or climbing shrubs, with alternate leaves

having no stipules; they have an indefinite number of stamens and the fruit is an aggregate of achenes or small nuts; the sepals often take on the character of petals."

This group of plants constitutes the Natural Order of the "

Eanunculaceae."

Now this Natural Order has beer, divided into 27 Genera, some of which are garden plants such as the anemone and the

delphinium; some are medicinal plants like the aconite and

hellebore, and each of these Genera is again sub-divided into

Species. How this has been done for our yellow buttercups is ex

plained in the article below, by Captain Chase. This sub-division into

" Species

" is continually going on; as botanical knowledge

increases fresh points of difference are being always discovered, and up to now about 500 Species among the 27 Genera of the

Natural Order "

Eanunculaceae "

have been differentiated.

BUTTERCUPS.

By C. D. Chase, M.C., M.A.

Of the yellow flowered species of the great genus Banunculus

(which contains the world over some five hundred species) we have in the N.E. of Ireland eight representatives. In order of

flowering the first is the Lesser Celandine (1), which in mild seasons can be picked as early as the first week in January. Le^s common and only to be found in woods and shady places is

Goldilocks (2) (some of our plants have names almost worthy of their beauty), the next species to appear, generally in April. Then in May come three flowers rather puzzling to the beginner on

account of their close resemblance to each ather, which all have

the name of Buttercup or Crowfoot. The first, the Creeping Buttercup* (3) is of a somewhat darker yellow than the other two, and its flowers are a little larger; its furrowed flower stalks, or

peduncles as they are called botanic-ally, also distinguish it from the taller Upright Buttercup (4) whose leaves, another distinction, are more deeply cut. Our third member of this group is the

Bulbous Buttercup (5), to be known by its root, from which it

gets its name, but still more by its reflexed sepals. In May also

appears the Lesser Spearwort (6) to be found in wet places. Its leaves are not cut as in the three preceding species, but are entire. In June, also in wet places, often actually growing in the water we find the Celery-leaved Crowfoot (7), which with its very small,

pale yellow petals is not likely to be mistaken ior any of its near

*Known in the country as "Sitfast"

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