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ANNALS OF BOTANY

VOL. V

O^forb

PRINTED AT THE CLARENDON PRESS

BY HORACE HART. PRINTER TO THE UNIVERSITY

Annals of Botany

!

EDITED BY

ISAAC BAYLEY BALFOUR, M.A., M.D., F.R.S.

QUEEN’S BOTANIST IN SCOTLAND, PROFESSOR OF BOTANY IN THE UNIVERSITY AND KEEPER OF THE ROYAL BOTANIC GARDEN, EDINBURGH

SYDNEY HOWARD VINES, M.A., D.Sc., F.R.S.

FELLOW OF MAGDALEN COLLEGE, AND SHERARDIAN PROFESSOR OF BOTANY IN THE . UNIVERSITY OF OXFORD

W. T. THISELTON-DYER, C.M.G., M.A., F.R.S.

DIRECTOR OF THE ROYAL GARDENS, KEW AND

WILLIAM GILSON FARLOW, M.D.

PROFESSOR OF CRYPTOGAMIC BOTANY IN HARVARD UNIVERSITY, CAMBRIDGE, MASS., U.S.A.

ASSISTED BY OTHER BOTANISTS

VOLUME V

With XXVII Plates, in part coloured, and 4 Woodcuts

London

HENRY FROWDE, AMEN CORNER, E.C.

OXFORD: CLARENDON PRESS DEPOSITORY, n6 HIGH STREET

'

ERRATA.

Page 6, footnote 2, after * wiss.’ insert Bot.’

35, line 6, for germ-spore read germ-pore.’

63, for corrections in the Revised List of the British Marine Algae see

the ‘Appendix’ on p. 522.

122, line 21 ,for ‘Zeille’ read ‘Zeiller-.’

297, Postscript, line 11, omit ‘not’ after Cucurbitaceae.’

29, for ‘when’ read ‘where.’

CONTENTS

520.^^

*M>I

'I'jLaJtff’

No. XVII.

PACE

VAIZEY, J. R. (the late). On the Morphology of the Sporophyte of

Splachnum luteum. (With Plates I and II) ... i Saunders, E. R. On the Structure and Function of the Septal glands

in Kniphofia. (With Plate III) n

Barclay, A. On the Life-history of Puccinia Geranii sylvatici, Karst.,

var. himalensis. (With Plate IV) . . . . . 27

Farmer, J. Bretland On Isoetes lacustris, L. (With Plates

V and VI, and Woodcut 1) 37

Holmes, E. M., and Batters, E. A. L.— A Revised List of the

British Marine Algae 63

No, XVIII. [AqaJ)

Bower, F. O. Is the Eusporangiate or the Leptosporangiate the more

primitive type in the Ferns? (With Plate VII) . . .109

Johnson, T. Observations on Phaeozoosporeae. (With Plate

VIII) 135

Barber, C. A. The Structure of Pachytheca. II. (With Plate IX) 145 Baker, J G. On the Vascular Cryptogamia of the Island of St.

Vincent. (With Plates X and XI) 163

Scott, D. H. On some points in the Anatomy of Ipomoea versicolor,

Meissn. ( With Plates XII and XIII) 173

Baker, J. G. A Summary of the new Ferns which have been dis- covered or described since 1874. (With Plate XIV) . . 181

NOTES.

Thiselton-Dyer, W. T. Note on Mr. Barber’s paper on Pachytheca 223 Webber, H. J. On the Antheridia of Lomentaria. (With Woodcuts

2 and 3) 226

Thiselton-Dyer, W. T. Ectocarpus fenestratus .... 227

Type-specimens of Mrs. Griffiths . . 228

No. XIX.

Campbell, Douglas Houghton. Contributions to the life-history

of Isoetes. (With Plates XV, XVI, and XVII) ... 231

Scott, D. H., and Brebner, George. On Internal Phloem in the root and stem of Dicotyledons. (With Plates XVIII, XIX,

and XX) 259

Baker, J. G. A Summary of new Ferns which have been discovered

or described since 1874 ( continuation ) ..... 301

VI

Contents.

Elliot, G. F. Scott. On the Fertilisation of South African and Madagascar Flowering Plants. (With Plates XXI, XXII, and XXIII) .

NOTES.

Hemsley, W. Botting. Prolonged Vitality of the Seeds of Sea^

Shore Plants

A Burmannia in Japan

Flora of the Solomon Islands .

- On Rhynchosia antennulifera

m\)

Vines, S. H. On the presence of a Diastatic Ferment in Green Leaves

No. XX. lf\f<rT

Fry, R. E. On Aggregations of Proteid in the cells of Euphorbia splendens. (With Plate XXIV) ... . .

Solms-Laubach, H. Graf zu. On the Fructification of Bennettites gibsonianus, Carr. (With Plates XXV and XXVI)

Baker, J. G. A Summary of new Ferns which have been discovered

or described since 1874 ( concluded )

Hemsley, W. Botting. New Solomon Islands Plants. (With Plate XXVII)

NOTES.

Massee, George. A new Genus of Tubercularieae. (With Wood-

cut 4)

A new Cordyceps .......

Green, J. R. On the occurrence of Diastase in Pollen Wager, Harold. On a nuclear structure in the Bacteria Scott, D. H.-— On the origin of Polystely in Dicotyledons .

Holmes, E. M., and Batters, E. A. L. Appendix to Revised List of British Marine Algae

333

406

407 407 407 409

4i3

419

455

501

509

510

511

513

514

518

INDEX

PAGE

A. ORIGINAL PAPERS AND NOTES.

Baker, J. G.

A Summary of the New Ferns which have been discovered or

described since 1874. (With Plate XIV) . . 1 81, 301, 455

On the Vascular Cryptogamia of the Island of St. Vincent. (With

Plates X and XI) ......... 163

Barber, C. A. The Structure of Pachytheca. II. (With Plate IX) 145 Barclay, A. On the Life-history of Puccinia Geranii sylvatici, Karst.,

var. himalensis. (With Plate IV) . . . . . 27

Batters, E. A. L. See Holmes.

Bower, F. O. Is the Eusporangiate or the Leptosporangiate the more

primitive type in the Ferns? (With Plate VII) . . . 109

Brebner, George. See Scott.

Campbell, Douglas Houghton. Contributions to the Life-history

oflsoetes. (With Plates XV, XVI, and XVII) . . .231

Elliot, G. F. Scott. On the Fertilisation of South African and Madagascar Flowering Plants. (With Plates XXI, XXII, and

XXIII) 333

Farmer, J. Bretland. On Isoetes lacustris, L. (With Plates V and

VI, and Woodcut 1) ........ 37

Fry, R. E. On Aggregations of Proteid in the cells of Euphorbia

splendens. (With Plate XXIV) 413

Green, J. R. On the occurrence of Diastase in Pollen . . . 511

Hemsley, W. Botting.

Prolonged Vitality of the Seeds of Sea-shore Plants . . . 406

A Burmannia in Japan 407

Flora of the Solomon Islands ....... 407

On Rhynchosia antennulifera . . . . . . .407

New Solomon Islands Plants. (With Plate XXVII) . . . 501

Holmes, E. M., and Batters, E. A. L.

A Revised List of British Marine Algae 63

Appendix to Revised List of British Marine Algae . . . 518

Johnson, T. Observations on Phaeozoosporeae. (With Plate VIII) 135 Massee.

A new Genus of Tubercularieae. (With Woodcut 4) . . . 509

A new Cordyceps 510

Saunders, E. R. On the structure and function of the Septal Glands

in Kniphofia. (With Plate III) 11

Vlll

Index .

Scott, D. Ii.

On some points in the Anatomy of Ipomoea versicolor, Meissn.

(With Plates XII and XIII ) 173

On the origin of Polystely in Dicotyledons . . . . .514

Scott, D. H., and Brebner, George. On Internal Phloem in the root and stem of Dicotyledons. (With Plates XVIII, XIX,

and XX) . 259

Solms-Laubach, H. Graf zu. On the Fructification of Bennettites

gibsonianus, Carr. (With Plates XXV and XXVI) . . 419

Thiselton-Dyer, W. T.

Note on Mr. Barber’s paper on Pachy theca 223

Ectocarpus fenestratus . . . . . . . . .227

Type-specimens of Mrs. Griffiths 228

Vaizey, J. R. (the late). On the Morphology of the Sporophyte of

Splachnum luteum. (With Plates I and II) ... 1

Vines, S. H. On the presence of a Diastatic Ferment in Green Leaves 409 Wager, Harold. On a nuclear structure in the Bacteria . . . 513

Webber, H. J. On the Antheridia of Lomentaria. (With Woodcuts

2 and 3) . . .226

B. LIST OF ILLUSTRATIONS.

a. Plates.

I, II.

III.

IV.

V, VI. VII. VIII. IX. X, XI.

XII, XIII.

XIV.

XV, XVI, XVII. XVIII, XIX, XX.

XXI, XXII, XXIII.

XXIV. XXV, XXVI. XXVII.

b. Woodcuts.

On Splachnum luteum (Vaizey).

On Septal Glands of Kniphofia (Saunders).

On Puccinia Geranii sylvatici, Karst., var. himalensis (Barclay).

On Isoetes lacustris, L. (Farmer).

On the primitive type in the Ferns (Bower).

On Phaeozoosporeae (Johnson).

On Pachytheca (Barber).

On the Vascular Cryptogamia of the Island of St. Vin- cent (Baker).

On the Anatomy of Ipomoea versicolor, Meissn. (Scott).

Summary of new Ferns (Baker).

On Isoetes (Campbell).

On Internal Phlpem in Dicotyledons (Scott and Brebner).

On Fertilisation of South African and Madagascar Plants (Scott Elliot).

On Proteid in Euphorbia splendens (Fry).

On Bennettites gibsonianus, Carr. (Solms-Laubach). New Solomon Islands Plants (Hemsley).

1. On Isoetes lacustris, L. (Farmer) .

2-3. On Antheridia of Lomentaria (Webber) . 4. On Plobsonia and Cordyceps (Massee). .

43

226

510

On the Morphology of the Sporophyte of Splachnum luteum.

BY THE LATE

J. R. VAIZEY, M.A.,

of Peterhouse, Cambridge .

With Plates I and II.

[After Mr. Vaizey’s death there were found among his papers a number of drawings, which were intended to illustrate his memoir on the Sporophyte of Splachnum luteum : a preliminary account of his observations had already appeared in the Proceedings of the Royal Society. There were also found a few sheets of manuscript, consisting chiefly of a description of the structure as illustrated by the figures, but the discussion of the morphological question which is indicated in the last paragraph of the paper in the Pro- ceedings of the Royal Society was not entered upon. It has been found possible, by putting together these fragments, to present them in a connected and intelligible form, so as to demonstrate the careful observation and draughtsmanship which characterised Mr. Vaizey’s work : excepting a few verbal alterations, the text, though rearranged, is entirely his own. The Editors are indebted to the Council of the Royal Society for permission to make use of the paper which appeared in the Proc. Roy. Soc. No. 274, Dec. 1888].

THE investigations of Haberlandt \ published in the latter part of 1 886, together with the results of investigations of my own, which were then just completed, and communi- cated to the Linnean Society2 early in 1887, convinced me of the importance of obtaining further knowledge of the highest development to which the sporophyte of the Mosses attains, as being likely to throw light indirectly on the phylogeny of the higher Cryptogams and Phanerogams. Inquiring into the

1 Beitrage zur Anatomie und Physiologie der Laubmoose ; Jahrb. fur wissens. Bot., vol. XVII.

2 Vaizey: On the Anatomy and Development of the Sporogonium of the Mosses. Linn. Soc. Joum., Bot., vol. XXIV.

[Annals of Botany, Vol. V. No. XVII. December 1890.]

B

2

Vaizey . On the Sporophyte

matter, I found that Splachnum luteum , Splachnum rubrum , and some few other forms were the most likely to yield the best results ; I determined, therefore, to obtain material for investigating their morphology. These forms being arctic or subarctic, I put myself in communication with Professor Axel Blytt, of Christiania, to find out if he could either procure me material properly preserved for the purpose, or put me in the way of obtaining material if I went myself to Norway. From my correspondence with Professor Blytt, I concluded that the only really practicable course was to go myself, and obtain my own material in the different stages in which I required it. To carry out this project, I applied for, and was granted, assistance by the Royal Society. I, therefore, now tender to the Society a brief outline of the first of my results.

I obtained after considerable search, in which I was fortu- nate in having the invaluable assistance of Professor Blytt and Dr. F. C. Kiaer, whose knowledge of the habitats of Norwegian Mosses is notorious, a large quantity of Sp. luteum in many different stages of development ; of Sp. rubrum I only obtained one specimen ; but beyond the mere difference of colour there is little or no difference between the two species. The material was obtained in the marshy land on the top of the watershed between the River Glommen and Lake Miosen, and on the south-eastern side of the Dovrefjeld region.

In the sporophyte of Splcichmim luteum we have a structure with a remarkable similarity fo an umbrella, the handle-end of which is inserted in the tissues of the oophyte, and is known as the foot (Fig. i). The seta is much elongated, frequently attaining a length of 150 mm. : it bears the umbrella-like expansion, the apophysis, at the top just below the sporangium. It is the structure of the apophysis and certain of the organs of the sporophyte with which we are now concerned.

A transverse section through the vaginula, including the foot of the sporophyte, shows that the tissues of the oophyte in this part contain a considerable quantity of organic sub-

3

of Splachnum luteum .

stance, and this is seen to be more particularly the case in the layers of cells next to the foot (Fig. 3) 1. The foot itself is seen to consist of a cylindrical mass of parenchyma, with an external layer of epidermal cells of a somewhat columnar form, which contain a considerable quantity of protoplasm, together with large distinct nuclei (Fig. 4). The protoplasm of these cells is found to be aggregated towards the peripheral surface, the nucleus being usually found in the mass of proto- plasm next to the outer wall of the cell. The large vacuoles of these cells are traversed by fine protoplasmic filaments. These cells, as. well as those of the cortical layer beneath the epidermis, contain a number of very small protoplasmic bodies, which are found congregated in large numbers round the nuclei of the cells, there being also some in other parts of the cell, both in the peripheral layer and in the fine proto- plasmic filaments traversing the vacuole. In the epidermal cells these bodies are particularly numerous, and are found principally in the aggregated mass of protoplasm on the outer side of the cells. These bodies may, I think, be safely re- garded as leucoplastids. From their number and position, I am inclined to believe that they are concerned in absorbing substances from the tissue of the oophyte for the nourishment of the sporophyte. No starch has been found in the foot. The general relation of the foot to the vaginula is shown in longitudinal section in Fig. 5.

In the centre of the foot there is a definite central strand consisting of two kinds of tissue, an outer phloem-like layer of cells containing protoplasm by means of which it is probable that organic substance travels, and an inner strand of very thin-walled cells without any protoplasmic contents 2 which conduct the water up the seta (Fig. 6 and 6 bis). In the foot the protoplasm of the phloem-like cells is aggregated in each cell towards the periphery as in the epidermal cells, but there are no plastids present. The strand of thin-walled

1 [N. B. The cell-contents are not drawn in Fig. 3.]

2 Cf. Vaizey, loc. cit. The terms leptophloem and leptoxylem have been used to indicate these tissues. For fuller explanations, see paper referred to.

4

Vaizey. On the Sporophyte

empty cells1 I have been able to prove in other species of Splachnum conveys the water absorbed by the foot up the seta into the tissues of the apophysis.

The seta has a distinct epidermis beneath which there is a layer of sclerotic supporting-tissue, and then a layer of parenchyma, the two together forming the cortex. In the centre is the central strand, which in the lower end of the seta has almost the same structure as that described for the cen- tral strand of the foot, from which it is distinguished by being larger and less distinctly delimited from the cortex (Fig. 7). Higher up in the seta there is a large intercellular canal formed in the middle of the axile strand of thin-walled empty cells which extends for nearly its whole length. This inter- cellular space is lysigenous in origin. A similar passage or canal occurs in several other species (Fig. 8).

A longitudinal median section through the umbrella-shaped apophysis (Fig. 9, Plate II) shows that the central strand here swells out into a large pear-shaped mass of cells which, in the mature sporophyte, contain no protoplasm, and even in the younger states only a very small quantity with small, incon- spicuous nuclei. Chlorophyll-bodies are absent except in the two outermost layers of cells, even in the youngest specimens observed, and even here there are only a very few. The cells are all thin-walled, and cubical in shape, with no intercellular spaces between them. In this tissue, which may be regarded as a kind of aqueous tissue, large masses of crystalline in- organic matter were frequently found.

Outside the aqueous tissue (Fig. 10) there is a quantity of parenchymatous tissue, with numbers of communicating inter- cellular spaces. The cells all contain large numbers of chlorophyll-bodies. This tissue extends into the umbrella- shaped organ. On the upper surface in the proximal region the cells are arranged close to one another, and show a dis- tinct tendency to an elongation of their axes in a direction vertical to the surface, thus forming a palisade-tissue similar

1 Vaizey : Note on the Transpiration of the Sporophore of the Musci. Annals of Botany, vol. I.

5

of Splachnum luteum .

to that in the tissues of the vascular plants h This is rendered more striking by a comparison with the parenchyma of the lower surface in the same region, where the cells are much elongated in a direction parallel to the surface, and with very much larger intercellular spaces. The distal region of the apo- physis shows that the cells of both upper and lower surfaces have undergone a considerable lengthening in the direction parallel to the surfaces, but that the upper as compared with the lower has still a resemblance to palisade-tissue (Figs, ii, 12).

The epidermis covering the apophysis is of a pale brown tint resembling most closely the epidermis of the leaf of a typical Phanerogam, the external wall of the cells being the thickest (Figs. 10, 12). On the upper surface of the part of the apophysis which is nearer the sporangium the epi- dermal cells are flattened ; as the periphery is approached they become cubical, and in young specimens are even columnar in form (Fig. 11). On the under surface the same state of things is found, the epidermal cells nearest the seta being very much flattened. There is distinct cuticularisation of the epidermal cell-walls, and a distinct cuticle is present on the external surface, as is shown by the action of Schulze’s solution. The outer walls of the epidermis are thicker on the upper side of the apophysis than on the under, and a cuticle is also present on the under surface of the apophysis. Cuti- cularisation does not extend completely through the walls of the epidermal cells ; the inner layers of cell-wall becoming bright blue with Schulze’s solution, thus showing that those layers consist of pure cellulose. A plate of cuticularised membrane extends down the middle of the radial cell-walls from the external cuticularised layer. As far as I could deter- mine, there were in the epidermal cells only a very few small chloroplastids present, in which starch is sometimes to be found, but only in small quantities.

1 Haberlandt {Joe. cit .) also makes a comparison between the chlorophyll- containing tissue of the sporophyte of the Mosses and the palisade-tissue of true leaves ; but in none of the forms which he investigated is this structure as striking as it is in S. luteum.

6

Vaizey . (9/2 the Sporophyte

There are a number of stomata on the upper surface of the apophysis, the position of which is shown in the diagram (Fig. 9) : one only is drawn in Fig. 10, although a median longitudinal section may pass through as many as three. Fig. 15 gives a surface view of a stoma from a young apo- physis at a time previous to the development of the sur- rounding epidermal cells into the radiate arrangement, which they assume in the mature apophysis (Fig. 16). The guard- cells are quite separate, as in the vascular plants, thus differing from the guard-cells of the stomata of the Polytrichaceae and Funaria . A transverse section (Fig. 13) through the middle of the stoma shows that the form of the lips is quite normal, here again differing from the Polytrichaceae1 (Fig. 18) and some other Mosses 2. The stoma opens into an intercellular cavity of considerable size (Fig. 13), the full extent of which is seen on comparing longitudinal (Fig. 14) with transverse sections (Fig. 13). The guard-cells of the stomata contain a considerable number of large and well-defined chloroplastids, thus differing from the rest of the epidermal cells. The action of Schulze’s solution shows that on the external surface of the stomata there is a distinct cuticle (Fig. 17), which extends through the stomatal opening and on to the inner surface of the guard-cells. The innermost layers of the cell-wall of the guard-cells swell up to a much greater extent, and become a much deeper blue with Schulze’s solution than do any of the rest of the cell-walls throughout the whole of the apo- physis. A similar state of things was found in the stomata of Polytrichum commune , where cuticularisation has extended completely through the whole thickness of the cell-walls of the ordinary epidermal cells, but in the guard-cells the inner layers swell up with Schulze’s solution, and are coloured deep blue.

A large quantity of starch is formed in the cells of the

1 Vaizey, on the Anat. and Develop, of the Sporogonium in the Mosses. Journ. Linn. Soc. vol. XXIV.

2 Haberlandt, Beitrage z. Anat. und Phys. d. Lanbmoose ; Jahrb. f. wiss. XVII. 1886. [Compare alsoE. Biinger, Bot. Centbl. 1890, Bd. XLII, p. 193, &c.]

7

of Splachnum luteum .

apophysis by the chloroplastids, each chloroplastid containing a number of separate starch-grains. When the apophysis is quite young, at this time being green, immediately on its beginning to become umbrella-shaped, and before the spores ripen, the starch begins to be formed. At a later stage the starch disappears, the starch-forming plastids, which before were large and well-formed, degenerate into small and com- paratively inconspicuous bodies, the starch apparently being used up in the formation of spores. In all probability there is at this period a formation of xanthophyll, which would account for the yellow colour of the apophysis in the mature condition of the sporangium, and hence the name of the species.

That the apophysis performs the functions of a leaf, and is therefore analogous with the leaves of vascular plants, I think there can now be no doubt. And as this structure is a development of the sporophyte, the possibility of its being also homologous , either directly or indirectly, suggests itself. I am myself inclined to believe that the two are homologous ; but to give a full discussion of that question would be beyond the scope of the present communication.

The structure of the spore-capsule is quite typical : it is covered by a dark reddish-brown epidermis, which is cuticu- larised. The outer walls of the epidermal cells are rather thin, but the radial and anticlinal walls are thickened in a peculiar and characteristic way (Fig. 19): it will be observed that on the thickened side-walls of the epidermis there are large pits of varying form, as seen when looking on to the walls in the plane of the section ; at the same time the walls which are at right angles show thickenings of an elliptical or cordate shape : similar thickenings occur in other species of Splachnum \ Beneath the epidermis there are two or three layers of cortical cells, and then the large intercellular space (I) in Figs. 9 and 10, characteristic of the Moss-capsule. The columella has the same structure as I described in a

1 VnilTemin, Sur les homologies des Mousses; Nancy, 1886.

8 Vaizey. On the Sporophyte

former paper1 in the sporogonium of Catharinea {A trichum). The peripheral portion of the columella consists of nearly cubical, or hexagonal cells, with longitudinal and transverse diameter approximately equal, while the central part of the columella is occupied by cells which are very distinctly elongated and narrow (Fig. io). The structure of the teeth of the peristome in this genus is so remarkable that I cannot pass it by without mention, although Lantzius-Beninga 2 did not omit to treat of it in his classical work on the peristomes of Mosses. On the radial walls of the cells which go to form the peristome there are a number of horizontal thickenings which in longitudinal section have a remarkable similarity of appearance to the thickenings in the protoxylem of Vascular Plants, and at the same time recall the thickenings in the elaters and cells of the walls of the sporangia of many Hepaticae.

[Here the MS. ends. Other figures, besides those now published, were also found among Mr. Vaizey’s papers ; but as they were not referred to in the MS. and did not form any connected series, it was thought best not to publish them. This is especially the case with some drawings illustrating the development of the sporogonium, which Mr. Vaizey had begun to study in Sjblachnum vasculosum, but the series is too fragmentary to be of material use.]

1 Vaizey, Anat. and Develop, of Mosses; Journ. Linn. Soc. vol. XXIV.

3 Beit. z. Kenntniss des Baues d. ausgew. Mooskapsel, in besonderem d. Peristomes; Nov. Act. Akad. Leopold. Carol, vol. XXII, 1847, p. 577.

of Splachnum luteum.

9

EXPLANATION OF FIGURES IN PLATES I AND II.

Illustrating the paper of the late Mr. J. Reynolds Vaizey on the Morphology of the Sporophyte of Splachnum luteun .

The descriptions are based upon short notes written by Mr. Vaizey upon the margins of the drawings.

Fig. I. Mature Plant of Splachnum luteum. c = oophyte. sp sporophyte. s = seta, a p = apophysis, c = capsule. ( x 2 ) .

Fig. 2. a— i successive stages of development of the sporogonium, illustrating the mode of origin of the discoid, or bell-shaped apophysis, a e are slightly enlarged, f—i are natural size, h is an old specimen in which the apophysis has become discoid.

Fig. 3. Transverse section of the foot of the sporogonium (/) and of the vaginula ( v ). The cells of the leptophloem, which are shaded, are full of protoplasm in the upper and middle part of the foot, in sections from the lower part they are empty. The cells within this layer are the leptoxylem ; they are empty and perform the function of conducting water. [N. B. The cell-contents of the external layer of the foot, though referred to in the text, are not drawn in this figure, but they are shown clearly in fig. 4.] Crouch § , oc. 4, reduced to two- thirds.

Fig. 4. This figure was not named by Mr. Vaizey, but it is believed to represent the external epidermal layer of columnar cells referred to in the text, in contact with the tissue of the vaginula. The MS. description is as follows : N. B. Little round bodies are plastids, stained with Hoffman’s blue, and haematoxylin, not stained by methylene-blue.’ Zeiss F, oc. 2.

Fig. 5. Apex of the foot of Splachnum luteum within the vaginula, as seen in longitudinal section. No magnifying power is stated.

Fig. 6. Transverse section through the central strand of the foot, from a section stained with haematoxylin. /. ph = leptophloem. /. xy = leptoxylem. Crouch

oc. 2 (reduced to f).

Fig. 6 bis. Longitudinal section of part of the central strand of the foot of Splachnum luteum , and of the cortex ( c ) immediately surrounding it. Mr. Vaizey notes that the section is not median but distinctly tangential, the faint lines in the leptoxylem (/. x) show where the cells next to those in section join on.’ 1. ph «= leptophloem. Crouch ^ obj., oc. 1, reduced to two-thirds.)

Fig. 7. Central part of a transverse section of the seta between 1 and 2 centimetres above the vaginula, showing the central strand of thin-walled cells of water-conducting tissue. Zeiss F, oc. 2, reduced to two-thirds.

Fig. 8. Transverse section of the mature seta of Splachmun luteum , showing the central lysigenous intercellular space. (Zeiss D, oc. 2.)

Fig. 9. Median longitudinal section of the upper part of the sporogonium. ^ = seta. ap apophysis, c. s central strand. ^ stomata. M = mesophyll. C capsule, cl = columella. As = archesporium. I = intercellular space. P== peristome. The area enclosed in the dotted lines is drawn on a larger scale in Fig. 10.

io Vaizey . On the Sporophyte of Splachnnm luteum.

Fig. io. Part of a similar section drawn on a larger scale, pal. palisade- parenchyma. sp. s = spore-sac. (Zeiss A, oc. 2, reduced to one-half.)

Fig. 11. Similar section of the edge of the apophysis showing the relation of epidermis and mesophyll (mes). (Zeiss obj. oc. 2.)

Fig. 12. Epidermis ( ep ) and parenchyma from the upper side of the apophysis. (Zeiss D, oc. 2.)

Figs. 13, 14. Views of stomata in transverse and longitudinal section, ep epidermis, g. st. guard-cell of stoma. (Zeiss D, oc. 2.)

Fig. 15. Young stoma in surface view. (Zeiss D, oc. 2.)

Fig. 16. Stoma and surrounding cells from a full-grown apophysis. (& obj., oc. 1.)

Fig. 17. Section through the guard-cells and epidermal cells from a transverse section of the apophysis of Splachnnm luteum.

Fig. 18. Section through a stoma of Polytrichwn commune. g= guard-cell. ep = cells of epidermis, c cortical parenchyma.

Fig. 19. Epidermis from the sporangium of Splachnum luteum in transverse section.

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VAIZEY.— ON SPLACHNUM LUTEUM

University Press, Oxford.

On the Structure and Function of the Septal Glands in Kniphofia.

BY

E. R. SAUNDERS,

Newnham College , Cambridge.

With Plate III.

AMONG the more recent additions to the literature which deals with the subject of septal glands in plants may be mentioned the papers of Grassmann 1 and Acton 2. Grassmann’s work gives an account of the general structure and distribution of septal glands, while Acton is chiefly con- cerned with the question of sugar-formation in the gland- cells. The wider subject of floral nectaries is treated of in the earlier papers of Bonnier3 and Behrens4, but none of these observers includes in his account a detailed description of the minute structure of the secretory cells. It was sug- gested to me that careful histological examination of these cells might reveal the existence of interesting relations between their structure and their manifestation of secretory activity. I therefore made a preliminary examination of the septal glands of various species of Kniphofia , Gladiolus , Narcissus , Agave , and Polygonatum , and was led to select the first of these plants as being the most suitable for investigation. The ovary is of small size in this genus, but this drawback is more than counterbalanced by the following obvious advantages : (i) the amount of nectar secreted is considerable ; a fully open

1 Flora, 1884. 2 Annals of Botany, 1888.

3 Ann. des. Sci. Nat. 1878-79. 4 Flora, 1879.

[Annals of Botany, Vol. V. No. XVII. December 1890.]

12

Saunders —On the Structure and

flower contains two or three drops of very sweet nectar at the base of the flower tube, and (2) the size of the secretory cells is comparatively large.

After trying various hardening reagents, I found that the structure of the cells was best preserved by treatment for three or four days with a 2 per cent, solution of ammonium or potassium bichromate (as a rule the former gave the best results). The ovaries only were hardened, and in order to ensure that the solution should penetrate as rapidly as pos- sible, portions of the external cuticle were stripped off, and the extremities of the ovary itself were removed by trans- verse section, before it was placed in the hardening fluid.

I examined the following species of Kniphofia ; K. nobilis , media , aloides var. max.> and uvaria , but I was unable to detect any differences in the histological appearances which I could regard as specific ; the following account therefore applies equally to them all. I propose to describe I. The position and course of the glands, and

II. The minute structure of the cells which compose the gland.

I. Position and Course of Glands.

The glands are normally three in number, one occurring in each septum of the trilocular ovary ; they are simple and extend almost throughout the whole length of the septum (Fig. 2). Each arises at a level only slightly above that at which the ovary-cavities make their appearance, and here forms a compact group of coherent cells, which however split apart almost immediately, and surround a central cavity, the lumen of the gland. The lumen opens on to the external surface immediately below the base of the style (Fig. 2), and here the gland-cells which bound the lumen become con- tinuous with the epidermal cells of the external wall of the ovary. The short passage (leading on to the surface) in which this transition takes place may be conveniently termed the neck of the gland (Fig. 2, n.). In transverse section the glandular area has -roughly the form of an ellipse, the long

Function of the Septal Glands in Kniphofia. 1 3

diameter of which coincides with that of the septum. This area is fairly constant at all levels except that of the neck and of the extreme base of the gland, where it diminishes, gradually in the latter case, rather more rapidly in the former. The lumen is wider in the upper and lower extremities of the gland than in the middle (Fig. 3), where the cells on either side approximate, especially at the inner margin of the gland.

II. The Minute Structure of the Cells which

COMPOSE THE GLAND.

The gland-tissue consists of

(1) A single layer of epidermal cells ;

(2) A variable number of layers (generally four or five) of

modified parenchymatous cells, which lie behind the epidermal cells, and to which I shall henceforth refer as the sub-epidermal cells.

Behind the sub-epidermal cells lie the ordinary unmodified parenchymatous cells of the septum, and the fibro-vascular tissue. There are from eight to twelve small fibro-vascular bundles in each lateral half of the septum ; these bundles arise at fairly regular intervals, and are offshoots from the fibro-vascular tissue running vertically in the central axis of the ovary. They bend outwards at a more or less acute angle, and, running nearly horizontally outwards in the septum, finally curve round into the wall of the ovary and there resume their vertical course (Fig. 1 ,/. v .). Since these bundles sometimes run in the unmodified parenchymatous tissue of the septum, and sometimes between it and the glandular tissue, they do not form such a well-marked line of separation between the two, as is the case, e. g. in some (?) species of Gladiolus , in which plants moreover their course in the septum is vertical.

To return to the minute structure of the gland-cells.— I shall begin by describing the histological appearances which are exhibited by a typical [a) epidermal, and ( b ) sub-epider- mal cell when quite young, such cells for example as are to

I4

Saunders.— On the Structure and

be seen in a very young flower-bud, and shall then trace the changes which take place in (a) cell-wall, (/3) nucleus, (y) cell- contents, during the period of development from the young bud to the fully open flower, noting finally the extent to which these changes are dependent on the relative position of the cells.

A. Very young Bud (Fig. 4).

(a) The epidermal cells are cubical to columnar in shape,

and somewhat smaller than either the sub-epidermal cells, or the unmodified parenchymatous cells of the septum.

(a) The external wall (bounding the lumen) is un- cuticularised, and at first exhibits a plane surface ; the lateral and basal walls are continuously applied to those of the neighbouring cells.

(/3) The nucleus occupies a very large proportion of the cell-cavity, it is generally spherical or oval in shape, and lies centrally; one, two, or three nucleoli are often present.

(y) The protoplasm occupying the rest of the cell is dense and granular, and in that part of it which im- mediately surrounds the nucleus minute starch-grains very soon make their appearance.

(b) The histological modifications of the sub-epidermal cells

are always most marked in those lying immediately beneath the epidermis, and gradually become less and less so in those lying further from the lumen, so that there is no sharply defined boundary between these deeper layers and the unmodified parenchymatous cells of the septum, but a gradual transition from the one to the other.

(a) The sub-epidermal cells vary considerably in shape, but as a rule all three diameters are roughly equal. Their arrangement is less regular and compact than that of the epidermal cells, and this character becomes gradually more marked in the deeper layers, where inter-

Function of the Septal Glands in Kniphofia . 1 5

cellular spaces occur, and where the cells are generally slightly larger than those which are immediately hypo- dermal.

(fi) The nuclei resemble those of the epidermis, but are smaller in proportion to the size of the cells.

(y) The protoplasm is less dense, and the starch-grains more numerous than in the epidermal cells.

Starch is present in the unmodified parenchyma of the septum, and occurs also in abundance in the central axis, where the grains are much larger.

B. An older Bud (Fig. 5).

(a) The epidermal cells are about the same size as the sub-epidermal cells, or only very slightly smaller.

(a) The external wall is slightly convex, and has under- gone an increase in thickness ; in the largest buds it is seen to be differentiated into two layers, a very narrow external one which is sharply defined, and a broad in- ternal one, the inner outline of which is much less