The fern world

Front matter

22101730980

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Chapter I. — The Germs of Fern Life . . . . . 9 II. — Conditions of Growth 13

III. — Structure 16

IV. — Classification 28

V. — Distribution . . . . • • 32

VI. — Uses 41

VII. — The Folk-lore of Ferns ..... 48

PART II. Fern Culture

Introduction 55

Chapter I. — Soil and Aspect ...... 59

II. — General Treatment ..... .63

III. — Propagation ...... ,67

IV. — A Fern Valley . 73

V. — Subterranean Fern Culture . . . . 76

VI. — A Fern Garden ...... 78

VII. — Fern Rockeiy ....... 84

VIII. — A Fern House 89

IX. — Pot Culture of Ferns ..... 92

X. — Ferns at Home ....... 98 a

X

CONTENTS.

PAET III.

Feen Hunting.

-r I’AGE

Chaptee I. — Fern Holidays ....... 107

II. — Fern Collecting 109

III. — Frond Gathering 115

PAET IV.

I.NTBODUCTION 123

O^iAPTEU I. — Down a Combe to the Sea . .... 127

II. — Tlie Valleys of the Lyn ..... 133

III. — The Valley of the Eocks ..... 150

IV.— Clovelly 152

V. — Sea and Sky and Waving Green . . . 167

VI. — Torbay 176

VII. — The South-east Coast of Devon . . . 187

VIII. — The Home of the Sea Fern .... 192

PAET V.

Inteoddction 205

1. The Bracken {Pterin aquilina) ..... 213

2. The Hartstongue {Scolojpendriuvi vulgare) . . . 218

3. The Lady Fern {Athyrium fdix-foemina) . . . 227

4. The Hard Fern (Blechnum spicant) .... 237

5. The Eoyal Fern {Osmunda reyalis) .... 242

6. The True Maidenhair {Adiantum capillus- Veneris) . 248

7. The Annual Maidenhair {Gymnogramma leptophylla) . 257

8. The Mountain Parsley Fern {Allosorus crispus) . . 261

9. The Bristle Fern {Trichomanes radicans) . . . 269

10. The Moonwort {Botrychium lunaria) .... 274

11. {Ophioglosswm vulgatum) . . 278

12. The Little Adders-tongue {Ophioglossum lusitanieum) . 281

CONTENTS. XI

PA OB

Beitish Feens {continued) —

13. The Common Polypody {Polypodium vtdgare) . . 287

14. The Mountain Polypody . 292

15. The Three-branched Polypody {Polypodium dryopteids) 296

16. The Limestone Polypody {Polypodium calcareum) . 300

17. The Alpine Polypody {Poly podium alpestre) . . 304

18. The Hard Prickly Shield Fern {Polystichum aculeatum) 308

19. The Soft Prickly Shield Feim {Polystichum angulare) . 312

20. The Holly Fern {Polystichum lonchitis) . . . 316

21. The Brittle Bladder Fern {Cystopteris fragilis) . . 320

22. The Alpine Bladder Fern {Cystopteris regia) . . 324

23. The Mountain Bladder Fein {Cystopteris montana) . 331

24. The Oblong Woodsia ( . . . 339

25. The Alpine Woodsia {Woodsia alpina) .... 343

26. The Male Fern {Lastrea Jllix-mas) . . . ■ . 346

27. The Broad Buckler Fern {Lastrea dilatata) . . . 350

28. The Hay-scented Buckler Fern {Lastrea recurva) . . 354

29. The Eigid Buckler Fern {Lastrea rigida) . . . 358

30. The Crested Buckler Fern {Lastrea cristata) . . 365

31. The Prickly-toothed Buckler Pern {Lastrea spinulosa) . 373

32. The Mountain Buckler Fern {Lastrea montana) . . 376

33. The Marsh Buckler Fern {Lastrea thelypteris) . . 381

34. The Forked Spleenwort {Asplenium septentrionale) . 385

35. The Alternate Spleenwort {Asylenium germanicum) . 389

36. The Kue-leaved Spleenwort {Asplenium ruta-muraria). 392

37. The Black Maidenhair Spleenwort {Asplenium adiantum-

nigrum) 398

38. The Lanceolate Spleenwort {Asplenium lanceolatum) . 403

39. The Rock Spleenwort {Asplenium fontanum) . . 407

40. The Green Spleenwort {Asplenium viride) . . .415

41. The Common Maidenhair Spleenwort {Asplenium tricho-

42. The Sea Spleenwort {Asplenium marinuni) . . . 424

43. The Scaly Spleenwort {Asplenium ceterach) . . . 429

44. The Tunbridge Filmy Fern {Hymenophyllum tunbtdd-

(jense 434

45. The One-sided Filmy Fern 439

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I

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THE FERN WORLD.

THE FEEN WOELD.

Introduction

A WORLD — apart — of dreamy beauty, of soft vapours and chequered sunbeams. A world — below the glare of noonday— filled with the most delicate and graceful of the forms which Nature^s God has made to clothe the earth with a mantle of green. A world where Nature’s own sweet music — the silvery music of the streamlet’s ripple — falls, gently cadenced, on the ear : or where the stillness of repose is unbroken, even by the hum of insect life. A world sometimes of darkness relieved but by the faintest gleam of light ; sometimes of open rocks and streams, where the roar of the torrent echoes over the mountain side, and rushing water reflects the golden colouring of the sun-rays. A fairy world hidden away under the covering of rugged rocks on the sea-shore, beneath moss-covered stones in the river’s bed, or in the depths of the primeval forest.

This same world of moisture and shadows is inhabited by various forms of plant life. The mysterious Fungus there

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THE EERN WORLD.

makes its home. Tliere^ too^ the Lichen creeps over its surface of stone or wood^ the Sea-weed clings to its dripping rock, and Mosses on floor of earth, wood, or stone, make a soft green carpeting. But above all these forms of vegetation, yet in some degree related to them, stand the Ferns — at once, though flowerless, the most graceful and beautiful of their lower woidd.

God, in His goodness, has, with a liberal hand, scattered these beautiful plants nearly over the whole of the earth^s surface, only the sterile regions of the frigid poles being deprived of them. But their abundance or scarcity in any part of the world depends upon the existence, in greater or less perfection, of those peculiar conditions of growth which these moisture-loving jolants require. In Europe, Asia, Africa and America, as well as in the islands of the seas, they are to be found, and both in troiDical and temperate climes. Over the whole world, more than three thousand distinct species have been discovered ; but the variations from the normal forms of these species reach a far larger number than three thousand.

It is curious and interesting to note the proportion borne by Ferns, in those great divisions of the woidd which we call zones,^ to flowering plants. Within the colder regions of the polar circles we have seen that they cease to exist. Just outside those regions, but within the boundary of the frigid zones they are found in the jaroportion of one Fern to eight flowering plants. In the toi’rid zone they stand in the proportion of one to twenty flowering plants, whilst in the temperate zones they are in the proportion of one to seventy flowering plants. In England and Wales Ferns

INTRODUCTION.

O are doubly as numerous in relation to flowering plants as in the temperate regions generally, and in Scotland the proportionate number is even somewhat greater as compared with those regions.

But it is in the tropics that Ferns acquire their greatest degree of development, for in the depths of the great

THE FEEN WORLD.

trojDical foi’estSj under the influence of the prevailing heat and humidity_, they attain the size of trees, giving to those forests a strikingly graceful aspect, and even in the open country adding a distinctly-mai’ked element of beauty to the charm of the scenery.

'^I’ree Ferns within the torrid zone grow twenty, thirty, forty, and flfty feet high, often exceeding even that height. Yet, majestic as are these great tropical Ferns when found growing in such situations, and under such circumstances, their size takes nothing from the grace of their forms. Indeed, they are as much superior in grace and beauty to the other arborescent growths of the forest, as the lesser species of this charming order of plants are superior to the rest of the vegetable kingdom. Naturally, therefore, the gigantic fronds of the great tree Ferns wave more gracefully iu response to the gentle motion of the wind than the more rigid branches of other forest tree growths. But their delicacy of form is due to the peculiar conditions under which they grow, and not least to the soft moisture which continually surrounds them. Those of the graceful family which are exposed to the sun’s rays, wear a duller hue, and have less of the depth and brilliancy of colour, and less of the graceful drooping habit which are so characteristic of the species which hide beneath the deepest of the greenwood shade, or snugly nestle under the semi- darkness of clefts on the mountain side, or great rocks on the sea-girt shore. Sunshine and the free play of the air give greater stability and rigidity to these plants, but rob them of some of their characteristic beauty. It is the peculiar combination of

INTRODUCTION.

heat, moisture, and shade in the great tropical forests that encourages not only the most graceful but the most luxuriant growths of tropical Ferns. Such conditions, indeed, are, more or less, always congenial to vegetation, and hence it is that as they abound to so great an extent in the tropics, it is there that we find the greatest perfection in the gorgeousness of Nature’s garments. There, too, it is that the animal as well as the vegetable world wears more deep, rich, and brilliant colouring than in our soberer temperate climes. Hence those climes cannot produce the most luxuriant growths of Fern life, or its most brilliant and goi’geous coloui'ing — neither the palm-like arborescent kinds, nor the gold and silver species which flourish in the tropics.

We nevertheless possess in our British Ferns a great wealth of beauty and grace, and in some parts of these islands we have them in such profusion as to constitute a distinct element in the beauty of the landscape, whilst oftentimes in our woods and forests they acquire a luxui’iance of growth almost suggestive of their tropical hend- quarters.

In whatever part, however, of the world these beautiful plants exist, whether in tropical or tempera t,e climes, they add a singular charm to their surroundings. Even when they grow on some wide expanded heath, under the open canopy of heaven, and in the full rays of the sun, they bring delicacy and grace to the scene, however wild and rugged it may otherwise be. If they grow beneath the shady underwood of a forest, they add a mystic and tender charm to the gloomy beauty of the place. When they are scattered over the great boulders which may stud the roaring bed of a mountain torrent, or are perched on the tiny islets of a

THE FERN WORLD.

gently murmuring stream, they are still the feature of crowning beauty as their waving fronds move responsively to the breeze, and kiss with their delicate tips the tumbling water, as if caressing the element which ministers to the most vital principle of their existence. When they clothe the sides and tops of jagged rocks, they appear as if placed there to soften the ruggedness of the stony surfaces ; and when they grow in the clefts of dwarfed or stunted forest trees, they help in such places to make amends for the incompleteness of Nature, whilst they lend their own halfmystic charm to minister to the pleasure of beholders.

CHAPTER I.

THE GERMS OE EERN LIEE.

In tlie wliole vegetable world there is nothing more beautiful thau the process by which Perns become developed from the almost mysterious atoms, which are, so to speak, the starting-points of their existence. It is indeed nothing less than marvellous that plants of such exceeding beauty and gracefulness, and characterized by such wonderful diversity of form, should be produced from germs which are in most cases almost infinitesimal, or so small as singly to be unseen by the naked eye. In what manner these minute atoms are produced by the parent plant, how nursed upon its fronds, how stored and protected from injury during the process of preparation for that final stage in their germ history at which they are launched forth to commence a separate existence in the Fern world, we shall subsequently inquire. We have now to speak of the germs as we find them fully endowed by the Creator with the mystic power which enables them to pass through their beautiful and wonderful stages of growth.

Here it will first be necessary to point out that the germ atom of the Fern — beautifully named a spore — has little

THE EE BN WOELD.

analogy Avith the seed of an ordinary plant. The spore differs from the seed both in the nature of its construction and in the principle of its growth. A seed is in truth a miniature plant compressed into a tiny space. This plantlet or embryo consists of two principal organs united to each other. The one is the radicle or the germ of the future root, the other is thepZMim6Ze or the germ of the future stem, which in the process of development gives rise to branches and leaves, or to smaller stems and leaves. Wherever or however a seed may fall, there can be no change in the respective functions of its radicle and plumule. The one is sure to strike downwards into the soil, and the other is equally sure to rise above the ground. ^

The spore is not so constituted, nor does it become developed after the manner of the seed. It consists, in fact, of a tiny cell, which is of various shapes in the different genera of Ferns, sometimes being globulai', sometimes oval, and occasionally angular in form, with an exterior that is sometimes plain, sometimes streaked, or otherwise beautifully marked, and either smooth or bristling with little points. From the part of this minute germ- cell which happens to lie / downwards proceeds the root, whilst from its upper portion proceeds the frond. When the spore has fallen into a congenial position for germination, the process of development commences by the enlargement and multiplication of the cell of which it consists. This cell becomes divided after a short time, and forms an aggregation of little cells, which take the shape when expanded of a minute patch, like a tiny leaf laid flat on the ground. This leafy scale, as it may be termed, is mostly irregular in shape, but is usually somewhat

THE GERMS OF FERN LIFE.

round or heart-shaped. Its colour is green, and it bears the somewhat euphonic name of prothallus. Under the prothallus — which attaches itself to the earth or rock by fine rootlets — begin to be produced a number of other little cells of a peculiar kind. They are in fact of two kinds, and may be called for the sake of distinction, sperm cells and embryo cells. One of the latter contains a frond-bud or imperfect germ, imperfect because it has to be fertilized before it can commence the process of development. The sperm cells contain minute, active, thread-like bodies called spermatozoids. At a certain stage in the germination of the spore, the frond-bud emerges from its cell, and the spermatozoids about the same time issue forth from their cells, and coming into contact with the bud or embryo, the latter becomes fertilized. Soon after this process has been completed, the spermatozoids lose their activity and finally disappear. The prothallus, too, commences to decay, and finally, with its little system of cells, it dies, leaving in its place only the fertilized frond-bud, which, however, at this stage has no defined likeness to the future and complete frond. The under portion of the frond-bud lying next the damp soil soon however begins to form the rootstock, which subsequently gives rise to the rootlets that absorb and convey to the plant the moistux'e without which it could not live, whilst from its upper portion proceeds the stalk.

Steadily the process of development continues, until at length a tiny Fern is produced, whose form and habit begin to assume a likeness to the form and habit of the parent plant. In all Ferns which are not annual, including the large majority of this class of plants, the process of development is

THE EEEN WORLD.

SO slow that it is generally two or three years before it is completed. This is the case with the small and herbaceous species, whilst in the case of the shrub-like and the tree Ferns, the period from the commencement to the completion of growth is considerably longer.

Not the least wonderful circumstance in connexion with the minute germs of Fern life is their singular vitality. The dust-like spores, if kept secure and diy for a long period of years, will often, even after such an interval, when subjected to the necessary degree of heat and moisture, commence and continue the process of development.

Chapter II. Conditions Of Growth

There is a wonderful adaptation of means to an end in tlie circumstances under which the germination and development of Fern spores take place. The same conditions of growth must exist for the germ as for the mature plant — Nature having wisely ordered that the spore shall be of such a construction that it cannot survive the influence of conditions which would be fatal to the full grown Fern.

The conditions essential to the growth of both spore and mature Fern are, generally, moisture, warmth, and shade. Unlike the gayer inhabitants of the vegetable kingdom. Ferns mostly avoid the sunshine and hide in shadow and misty gloom. In such positions it is that they delight to revel, and though their fronds may sometimes perchance play with the sunbeams, they must have moist crevices for their roots. These cannot indeed survive even the temporary absence of moisture, for in such circumstances they shrivel and die.

We have seen that Fern spores are almost infinitesimal atoms, countless myriads of which when blown from the frond having but the appearance of a tiny cloud of brownish dust. So light are these minute germs that they are readily

THE FERN WORLD.

borne away by tlie faintest breatli of wind. When dispersed from tlie receptacles in wbicli tbey have lain ensconced^ vast numbers of them undoubtedly perish through falling upon uncongenial soil^ or upon " stony places/ unprovided with crevices moist enough to shelter and nourish the delicate life of such minute germs. But in their very abundance,, Nature makes provision for the risks to which they are exposed. Tlie tiniest Fern is provided with the means of producing a vast and uncountable number of germs for the perpetuation and multiplication of its kind ; and when the proper moment ari’ives — that at which the fructification has reached its most perfect stage^ and the atomic life germs are separated from the parent plant — the light and aerial messengers are sent forth to seek in every corner of their immediate world, for the resting places which can supply the peculiar conditions of growth that ai’e essential to them.

From what has been said, it will be inferred that Ferns, though hardy in their own particular way, cannot survive an amount of drought that many other plants can bear without material injury. Hence it is only in those positions in which conditions of moisture can be perpetually maintained that spores can live. Indeed, after germination has commenced they hang upon the threads of an existence which is far more fragile than that of seeds, for the temporary withdrawal of shade and moisture would be fatal to their delicate life.

Spores oftentimes fall upon surfaces which, though sufficiently moist to allow of the commencement and continuation of germination, are not — either from the nature of the soil, or the position — suitable for the proper growth and development of the particular Ferns represented by the spores. Those whose

COJSIDITIONS OF GROWTH.

natural habitat is on the spongy soil which lies under the deep shelter of a forest would not find the sides of rock or wall congenial to their growth. The Sea Fern could not live on the expanse of an open forest glade, where the Brake often grows in wild luxuriance. Nor could the latter thrive on the damp sides of a dark sea-cave. The Fern of the plain is not the Fern of the dripping hollow, nor are the rock-andwall-loving species adapted to the soft soil of the spongy hedgetop. It sometimes happens that Ferns which delight in a depth of spongy soil, and in the damp luxuriance of the hedgebank are found growing on the almost bare sides of rock or wall. But in such situations they drag on but an unhealthy existence, and become shrivelled in size, ungraceful in form, and deficient in colouring.

The Common Polypody, the Hartstongue, and the Black Maidenhair Spleenwort for instance, are often found growing in stony places, their rootlets getting what moisture and nourishment they can from the tiny seams of earth or leaf-mould in the interstices between the stones. But forlorn - looking indeed are these rock-and-wall-gvowing specimens compared with those that are found in the moist hollows of pollard trunks, on the dark margins of rushing streams, or in depths of shady hedgebanks.

Chapter III. Structure

f

Having ventured thus far into the Peru world, we must pause ere we further pursue our explorations, in order to inquire concerning the structure and constitution of its wonderful and beautiful inhabitants. Their position in relation to the rest of the vegetable kingdom we shall discuss anon. Here our inquiry must be limited to the field suggested by the heading of this chapter.

Ferns, as we have seen, stand at the head of their lower world, and hence their structure more nearly approximates to the upper — and sunnier — world of flowering plants than any other members of their class. Like flowering plants, they have roots, stems, and leaves. Let us call the two latter by their proper names of caudices and fronds. The last-named designation is especially necessary as a means of distinguishing in Ferns those organs which, though in their appearance the most nearly like what we call leaves in ordinary plants, are nevertheless very different in some important particulars from leaves. The caudex, or stem, is the root-stock of a Fern. From it grow — downwards — the fibrous rootlets, and — upwards — the fronds. There are two

STEUCTDEE.

principal kinds of caudex. The one is generally upright and trunk-shaped — sometimes^ as notably in the case of tree Ferns, raised to some height above the ground ; the other is creeping in its habit, and is called a rhizoma. The rhizoma in some Ferns creeps along or with its circumference half under the surface of the ground. In other Ferns — the common Bracken is an instance — the rhizoma creeps quite underneath the surface, throwing up its fronds at intervals from its upper side, and sometimes descending to a considerable depth in the earth, whilst the rootlets, which are thin and fibrous, insinuate themselves into the damp earth, or into the soft veins of rock or stone on which the Fern may be growing, drawing thence by absorption, and conveying to the stem and frond the essential moisture.

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THE EEEN WOELI).

When the rhizomas uaerely creeja along the sui’face of the ground^ they ai’e frequently furnished with hairs, or thick scales, which give them a shaggy appearance, but serve as a protection to the succulent root-stock which they cover. These creeping stems are of various sizes in the various species, in some being little more than stout fibres, whilst in other species they are thick and fleshy. The rootlets, or root-fibres, are in the same way proportioned to the size of the rhizomas ; iia the larger species growing to some thickness, and in the smaller ones being but the tiniest of delicate filaments. From various parts of the upper side of the creeping rhizomas spring the fronds, and it thus happens that, as the former advance — dividing sometimes into

STKUCTUEE.

branches^ and penetrating tbe soil in all directions — the Fern multiplies^ often rapidly^ throwing up a miniature forest of waving fronds, and sending into the earth at each point where the rhizoma developes into green life a mass of fibres, which serve at these successive stages to infuse more vigour into the plant.

There is something very beautiful in the arrangement by which Nature provides for the collection by the rootlets of Ferns of the moisture which the latter require for their nourishment. In the earlier stages of growth it is found that the rootlets are mostly supplemented by fine hairs, which cover their surface, and, by capillary attraction — that most mysterious and wonderful power — absorb moisture from every damp surface, either of earth, stone, or rock. As the rootlets acquire age, they become oftentimes tough and why, insinuating themselves into the tiniest crevices, and often extending their progress to considerable distances from the root-stock. Should the situation of the plant be such that possible drought might deprive it of moisture, the rootlets, as if by instinct, penetrate deeply into the earth, bank, or rocky seam, in search of distant and moister crevices than those in the immediate vicinity of the caudex or rhizoma. In such cases, and after a Fern has remained undisturbed for years, the great mass* of these delicate fibres, ramifying in all directions, constitutes a marvellous and beautifnl system, built up as a protection against the plant^s great foe — drought.

Before we conclude our remarks on the root-stocks of Ferns, let us notice those which in a large number of the species are upright in form, and raised above the surface of

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THE EEHN WOELD.

the ground. Sometimes — and indeed in the majority of

instances — they are raised hut slightly, often not more than an inch above the ground level or bank on which they are growing. The upper portion of the root-stock is in such cases formed into a crown, which is the basis from which the fronds spring. The crown is practically formed of a circle, or circular cluster of fronds, of the bases of fronds in a fully-developed plant, and of the buds merely of the fronds in an undeveloped or unopened state. Of the position and arrangement of the fronds we shall have more to say anon. Here we have only to explain how the elongation of the ci’own is caused. Each yearns circlet of fronds as it decays leaves the bases of its stems upon the crown of the plant. These stem-bases, rising each year one stage higher, gradually heighten the crown, the various sets of fronds all leaving their lower parts in continuation of the process. We have already seen that this process is carried on oftentimes, where the conditions of growth are favourable, until the stem of the Fern is raised, as in the gigantic cryptogamic growths of the foi’est, to a height of as much as fifty feet. And from the crown of the plant at this height continue to be thrown out, as before, a beautiful circlet of fronds. There are some British Ferns which exhibit this same tendency to an elongation of the caudex, and one species exhibits a tree-like stem, which is often raised two feet or more from the ground. But the absence of the extreme heat and moisture of tropical climates prevents the stems of the majority of our native Ferns from exceeding the moderate length of two or three inches. From the crown of the caudex, and from various points along the upper side of

STRUCTURE.

the rhizoma — in Ferns witli creeping stems — spring the fronds. These consist of two distinct parts, which may be generally likened to a stalk and a leaf. What would correspond in an ordinary plant to a stalk is in Ferns named a stipes — plural stipides — whilst the upper portion, or the leafy expansion, is carried upon an extension of the stipes called a racJiis — plural rachides. In compound fronds the continuation of the stipes, or the mid-rib of the frond, is called the primary rachis. If the leaf be divided, with divisions having mid-ribs branching out on each side from the rachis, these mid-ribs become each a secondary rachis. We return, however, to the stipes, or stalk, of the frond. There is very considerable variety in the length and appearance of the stipes in the various kinds of Ferns. Sometimes it is so short that the lower leafy portion of the frond almost touches the crown of the root-stock. Sometimes it is of considerable length, and indeed there are varying and intermediate degrees of length in the different species. The colour and thickness also vary. Sometimes the stipes is thin and delicate ; sometimes stout and fleshy. In some species it is bared of any covering ; in others it is densely or sparsely covered with various-coloured, chaffytextured scales. Sometimes it is extremely brittle and herbaceous, and sometimes tough. Amongst the most beautiful forms of the stipes in Ferns are those which are clothed with scales. Occasionally they are so thickly covered that when they grow up in a close ch’clet around the crown ^ curious cup-shaped appearance to the plant, the inside of the cup being a mass of downy scales. The stipes tapers from its base, the rachis also getting smaller

THE PEEN WOELD.

towards the apex of the leafy portion of the frond. Both consist generally of tissue — in fibro-vascular bundles — which is mostly of a very succulent nature.

We now come to the leafy^ or most beautiful and gTaceful^ part of the frond. Here^ in the form and colouring of the various species^ we find almost infinite variations. The explanation of all the differences observable in these exquisite organs of Ferns would fill a large volume. Sometimes the leafy portion of a frond is simple and undivided in form, presenting the appearance of an even-edged leaf. Sometimes the leafy portion, though undivided, has its margin beautifully cut in, or indented, the indentation assuming various shapes, often being deeply incised. In other cases the incisions reach down to the rachis, or mid-rib, of the frond. From this form there is an almost infinite variety of divisions of the frond, the rachis, or mid-rib, giving origin to secondary mid-ribs, and these to others branching from them, and so on, each mid-rib bearing its leaflet, or series of leaflets, and the leaflets bearing their more or less indented lobes.