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XXI.—On sameJurassic Specimens ofSagenopterisTom M. Harris aa University of ReadingPublished online: 20 Feb 2012.

To cite this article: Tom M. Harris (1940) XXI.—On same JurassicSpecimens of Sagenopteris, Annals and Magazine of Natural History:Series 11, 6:33, 249-265, DOI: 10.1080/03745481.1940.9723675

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THE

ANNAU AND MAGAZINE OF

NATURAL HISTORY. [ELEVENTH SERIES .]

No. 33. SEPTEMBER 1940. -- XX.1.-On some Jurassic Specimens of Sagenopteris.

By TOM M. HARRIS, University of Reading.

THIS paper describes various sorts of Sagenopteris leaves and a small stem from the Middle Estuarine (Lower Oolite) of Cayton Bay, Yorkshire. They were collected by Mr. F. M. Wonnacott and deposited by him in the Geological Department of the British Museum.

In a well-known paper Thomas (1925) established the Caytoniales for two types of fruit from this locality; and with these he associated a microsporophyll and the leaf Sagenopteris. He was concerned with major features of morphology, and pointed out that much remained to be found out ; in particular the stem was unknown and the leaves of the two species very imperfectly differ- entiated. Thomas’s reference of Sagenopteris to the Caytoniales has been doubted by some, but supporting evidence was forthcoming (Harris, 1933) from a Liassic Caytonialean, and I hope later to publish new evidence from the fruits in the present collection. Nothing indeed in this paper confLicts with any important conclusion of Thomas’s.

The Sagenopteris leaves in this collection have been divided into the two species, S. phillipsi (sensu strieto) and S. colpodes; the one being the leaf of Gristhorpia, the other of Gaytonia. Thomas suggested this, but did not carry it through, leaving the bulk of the specimens unplaced ; but now, as the result of some lucky h d s and

Ann. & Mag. N . Hist. Ser. 11. Vol. vi. 17

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250 Mr. Tom M. Harris on some

a slightly modified technique, all the available specimens have been sorted. Thomas's difKculty was that the leaves showed a continuous range of form variants, and though he succeeded in recognizing some different types of cuticle, the majority of his leaves yielded no satisfactory cuticles. The lucky finds were some specimens with particularly well-preserved cuticles ; the new technique made it easy to recognize certain strongly contrasted characters of the cuticles even in the poorest specimens. Portunately it is the thicker upper sides which show these characters best.

The new technique is as follows :-a fragment of not more than 4 sq. mm. is taken fiom the lamina (the margin is best), and it is mounted in HNO, saturated with KClO, under a coverslip. It is left 12 hours, or the oxidation can be completed in 15 minutes in an incubator at 60" C. The coverslip is irrigated with NH,OH or NaOCl (acid being removed by blotting-paper). The oxidized meso- phyll soon dissolves, and the cuticles separate su6ciently if the coverslip is jerked; hot glycerine jelly can, if necessary, be sucked in afterwards. The cuticle *obtained is, of course, a small piece, but it will show plenty of the characteristic cells of the upper epidermis. About ten leaves can be examined in this way in an hour.

This technique yields better results than when larger fragments of lamina are macerated. It was observed that the acid scarcely acts through the intact cuticle, but chiefly at cracks and broken edges, where the mesophyll is exposed. Thus with a small piece the oxidation of the mesophyll is soon completed; in consequence, the de- struction of the cuticle by oxidation, which proceeds at the same time but more slowly, will not have gone far ; with a delicate and ill-preserved cuticle such destruction cannot be afforded. The convenience of this technique and its comparative harmlessness to the specimen are obvious.

Sagenopteris colpodes, sp. n. The following specimens from Yorkshire resemble

S. colpodes in their broad leaflets, but are not known to have identical cuticles.

1833. Qlossopteris phillipsi Brongn.: Lindley & Hutton, p. 177, pl. lxiii. fig. 1.

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Jurmsic Specimens of Sagenopteris. 251

1900 a. Sugen0pteri-s phiiuipsi (Brongn.) : Seward, p. 16, text-fig. 25. 1925. SagenopteriS phdlipsi (Brongn.) : Thomas, p. 334, pl. xv. fig. 51

(it is not clear whether the cuticles of this or a similar specimen is figured in text-fig. 12 0, d ) ; pl. xv. fig. 49, shows a petiole of identical cuticle structure.

Holotype.-V.26441. Diagnosis.-Leaf consisting of 3 petiole bearing four

broadly ovate leaflets, upper leaflets nearly symmetrical, lower ones with the midrib nearer the upper margin. Leaflets typically about half as broad as long, apex obtuse, base showing a very minute stalk. Midrib con- spicuous below but disappearing near the apex, veins prominent on the lower side, flush with the surface on the upper, forming a network which grows finer near the margin. Surface of leaf conspicuously sculptured, upper side showing bulging points in rows parallel with the veins, lower showing bars transverse to the veins. Hairs not apparent on surface.

Cuticle rather thin, lower thinner tha:i the upper; the upper showing cells of more or less rectangular shape, those over the veins elongated parallel with the veins, those between often transversely elongated ; walls of all cells only moderately distinct, sinuous or with jagged khickenings ; surface of cells obscurely sculptured. Lower cuticle showing cell outlines indistinctly, cells along the veins elongated, those between irregular and sinuous walled ; stomates oval, with a fine but distinct outline. Subsidiary cells unspecialized, their inner cutinized walls not extending under the guard cells. Surface of guard cells showing an oval '' vorhof," surface sometimes showing fine radiating striations. Trichomes frequent, especially along veins, consisting of a small thickened cell with a bulging surface.

Petiole showing similar trichomes on t.he underside, cells rectangular, in longitudinal rows, lateral walls showing jagged thickenings.

.The name refers to the sinuous cell-walls. X. colpodes is less abundant in this collection than

8. phillipsi ; all the best specimens have been figured ; but with these specimens are smaller leaf fragments of the same species; thus on the bedding plane with V.21886 are fragments of four other leaves and a Cuytoniu fruit, but no other species.

The cuticle of this species is thinner than that of 17"

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252 Mr. Tom M. Harris on, some

S. phillipsi and its cell outlines are less distinct, but sinuous cell-walls are usually conspicuous near the leaf margin. The dif6culty of ascertaining the nature of the epidermal cell-walls is sometimes increased by the preservation of straight-walled palisade cells and the existence of wrinkles along the veins and margins caused by crushing. In some leaves too the surface bears a thin and irregularly broken layer of wax.

NesophyZZ.-The surface sculpture has been already mentioned ; this is due not to the epidermis but to unequal thickness of the interior of the leaf. On maceration some specimens behave normally, yielding nothing but the cuticle ; others yield, at least in places, some internal tissue which adheres to the cuticles and tends to conceal their cell outlines. The bulges of the upper side are now represented by large squarish cells between which inter- cellular spaces occur; these cells adhere loosely to the upper cuticle. but their outlines are in no way related to those of the epidermal cells. These are regarded as palisade cells.

Similar, but less well-preserved walls adhering to the lower cuticle indicate transversely placed cells on the lower side of the leaf; these are regarded as cells forming a tissue which is both spongy mesophyll and transfusion tissue. The mesophyll appears to owe its preservation to the impregnation of the walls or protoplasm by oily matter, just as in the seed coat of Cuytoniu.

Petiole.-The specimen shown in fig. 1 H (obtained by bulk maceration), which shows two pairs of scars, was identi6ed because of its general form as a Sagenopteris petiole and as S. colpodes because of its trichomes and sinuous cell-walls.

The under cuticle is slightly thinner than the upper (the side bearing the leaflet scars), and is provided with trichome bases, none of which was seen on the upper side.

The strongly marked lateral walls show sinuous thickenings like those of the upper surface of the lamina; the end walls, however, are delicate. A number of trichomes occur, consisting of a thickened basal cell (sometimes surrounded by other specialized cells) bearing a thinly cutinized hair which may project 301-1. The surface of the cells shows the same h e sculpture as does the upper epidermis.

The cells form longitudinal rows.

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Jurassic Specimens of Sagenopteris.

Fig. 1.

253

Sagempteris colpodes, leaf and bract. B, leaflet fragment

shown also in I, V.26434, x1. C, leaflet fragment shown also in D, V.26434, X 1. E, small leaf from a bulk maceration (cuticle only), V.26435, x 4. F, x 4. G, small-leaf leaflet from bulk macera- tion (cuticle only), V.26436, x 4. H, petiole, showing four leaflet scars, from bulk maceration, V.26437, x 8. I, as B, x 4. (Some of the finest veins in D, F, G, I have probably been missed.)

A, leaflet fragment shown also in F, V.24708, x 1.

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254 On some Jurassic Specimens of Sagenopteris.

This specimen is worthy of note because while it agrees. with one of Thomas’s specimens (1925, p. 337, pl. xv. fig. 49), it disagrees with the one he showed in his text-fig. 12 C, D (a form with straight walls and no hairs), and which I would determine as a small leaf of S. phillipsi (sensu stricto) . That particular specimen was figured beside the cuticle of Caytonia sewardi in order to demonstrate agreement in structure, but, as some others have pointed out, it shows points of dis- agreement. The present specimen shows far more convincing agreement with C. sewardi.

Small leaf .-Bulk maceration yielded two specimens of bract-like organs. One (fig. 1 E) shows a scale- like leaf base, which at its base appears to include the point of abscission. This leaf base bears at its apex a minute petiole, at the sides of which are two blunt upward extensions. The petiole bears four minute oval leaflets.

The other specimen is an isolated leaflet of similar size but more hairy. In both specimens the cuticle gives indications of the veins, which form a network closely similar to that shown for S. phillipsi.

The cuticle is interesting. In both specimens the lamina is more thickly cutinized than is the foliage leaf; but there is very close general agreement in structure (on this the specific identification is based).

In specimen No. V.26435 (fig. 1 E) both sides are just like those of the lamina, except that the cuticle is rather thicker, the cells are smaller and form more regular longitudinal rows, their lateral walls are more distinct (especially on the lower side), and hair-bases are more numerous on the lower side and margin.

Specimen V.26436, an isolated leaflet, has an even thicker cuticle on both sides ; the cell outlines on the upper side are thick and show sinuous lateral walls but straighter end walls (thus approaching a petiole in structure), while the lower side shows many hair-bases, some normal and some vestigial stomates. The margin is densely covered with hairs.

The petiole (specimen V.26435) appears to resemble the petiole of the normal leaf shown in fig. 2 E.

The expanded base has a fairly thick cuticle. The under side, which is slightly thicker, bears a good many

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Fig. 2.

Sagenoptek colpodes, cuticle. A, small-leaf base, underside, V.26435 (fig. 1 H), x 200. B, palisade.

cells (adhering to upper cuticle), V.24708 a, x 100. C, stomate of .foliage leaf, V.26438, x 800. D, small-leaf base, upper side- showing a hair, V.26435, x 200. E, petiole, underside, 8.26437, ~ 2 0 0 . F & G, foliage leaf upper cuticle, V.26438, Fx800.. G x 200. H, foliage leaf, lower cuticle (a vein runs on the right)* V.26438, x 200.

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256

hairs. It shows rows of short cells with very thick sinuous lateral walls, and thick but straight end walls. The upper side shows similar cells, but the walls are less thickened and the surface is sculptured with longitudinal ridges.

The unusual thickness of cuticle of this small leaf suggests that it was a protective organ formed in an exposed position. Very possibly it was a transitional organ between a bud-scale and a foliage leaf. The greater thick- ness of the lower cuticle of the leaf base is in agreement with this view.

Mr. Tom M. Harris on some

Few, if any, hairs occur on this side.

Sagewpteris phillipsi (Brongn.) Presl. The following Yorkshire specimens agree in their form

with 8. phillipsi, but their cuticles have not been examined. 1828. Glossopteris phillipsi Brongniart, p. 225, pl. lxi. fig. 5 ; G i .

1829. Pecqteris pawijolia Phillips, p. 148, pl. viii. fig. 8. 1833. Cilossopteris phillipsi Brongn. : Lindley & Huttan, p. 177,

1835. Otopteris cunecata Lindley & Hutton, p. 203, pl. clv. 1838. Sagempteris phiuipsi (Brongn.) Presl, in Sternberg, p. 165. 1900. Sagenopterisphillipsi (Brongn.) : Seward, p. 11, pl. iii. @a. 7, 8. 1900 a. Sagenopteris phillipsi (Brongn.) : Seward, p. 162, pl. w u i .

1925. Sagenopteris phillipsi (Brongn.) : Thomas, p. 334, pl. XV.

1939. Sagempteris phillipsi (Brongn.) : Darrah, p. 339, text-fig. 174.

Seward (1900a, p. 162) gives references to citations of this species in the literature and to some non-British specimens of more or less similar form, and in 1910, pp. 480-482, of some later references.

I am unwilling to express any opinion on the identity of the various non-British specimens referred to 8. phillipsi or X. cuneatu.

1. Foliage leaf .-About forty specimens of Xagenopteris phillipsi were examined ; the best are figured, the remainder being less perfect leaves which show no features of special interest, With the exception of a few leaves of small size all have narrow lanceolate leaflets with a definite midrib. The veins are moderately conspicuous in some, indistinct in other specimens. A point of some interest is shown by the leaflet drawn in fig. 3 G ; the veins are traceable into the midrib, where they continue as distinct ridges for a considerable distance.

fig. 2.

pl. lxiii. figs. 2, 3.

figs. 2-4 ; text-figs. 24, 26 (25 is more like 8. colpodes).

figs. 50, 52, 53 ; text-fig. 11 C, d, ? 12 C, d.

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Jurassic Specimens of Sagenopteris.

i

Fig. 3.

D '

257

Sagenophi-is phillipsi leaf.

A-F, H, portions of leaves natural size, G, as A, x 4 ; I as B, x 4. A,V.26429. B, V.23935. C, V.24716. D, V.24673. E, V.26427. F, V.26427. H, V.26428.

It is possible that some of the fine veins in G and I have been anissed.

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258 Mr. Tom M. Harris on s m e

Three small leaves (fig. 6B, C, D) show a lamina. imperfectly divided into leaflets, and might be classified as S. phillipsi var. cuneata (the original cuneata shows two short leaflets instead of four). Their cuticles are normal, however ; there is thus no reason for regarding them as anything but an extreme form of this variable species, a conclusion in agreement with Seward (1900), who reduced cuneata from a separate species to a variety or, as it would now be termed, a “form.” Thomas (1925), on the other hand, regarded cuneata as a distinct species belonging to Caytonia, while typical S. phillipsi belonged to Gristhorpia. It is interesting that a com- parable specimen is known in S. nilssoniana (Harris, 1932, text-fig. 2 I?), and it is likely enough that they may be found for yet other species. In any case it is ‘clear that these rather small leaves are of more varied shape t.han the full-sized ones and more difficult to determine on their form alone.

The leaflet V.24677 (fig. 6 A ) is the longest figured in this species, being longer than the one distinguished by Seward (1900) as “ variety major.” Its cuticle is normal. -

Surface sculpture.-The surface is either smooth or shows faint striations in the vein-interstices at right angles to the veins. It is thus smoother than some specimens at least of S. coZpodes. The leaf appears to be glabrous.

Cuticle.-The cuticle is of moderate thickness or rather thin ; the upper side measured 3p, the under 1-5 p in a microtomed specimen.

The upper shows almost uniform straight-sided poly- gonal cells with strongly marked outlines. The cells along the veins only differ in being placed in obscure longitudinal rows. The surface of the cells is sculptured and appears obscurely mottled, this being only con- spicuous in a water mount, and in certain specimens a more or less clearly-marked border can be traced round the cell.

The lower shows polygonal cells and stomates in the vein meshes, more or less rectangular and elongated cells along the veins. The cell outlines are very distinctly marked by a fine but prominent ridge; the surface is obscurely sculptured.

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Jurassic Specimens of Sagenopteris. 259

Fig. 4.

N

Sqenopteris Phillip&, cuticle of foliage leaf. A, stomate from lamina, V.26430, x 800. B, cell of upper epidermis,

V.26430, X 800. C, petiole, thick side, V.26427 a (from the speci- men shown in 3 F), x 200. D, upper epidermis of lamina, V.26430, X 200. F, lower epidermis of lamina, V.26430, x 200,

E, petiole, thin side, V.26427 a, x 200.

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260 Mr. Tom M. Harris on some

Occasional cells are thickened and have a bulging surface, but no hairs occur.

The stomates have no definite orientation. They show an oval outline, and the guard-cell surface takes up

Fig. 5.

E

D

Sugenopteris phillipsi, stem, small-leaf, and bud-scale. A, leaf scar of stem shown in D, V.26427, x 8. B, bud-scale (shown

to the left of D under different lighting), V.26427, x 8. C, bud-scale (shown to the right of D), stippled pert detached and viewed by transmitted light, V.26427 b, x 8. D, shoot with small leaf and bud-scales, drawn immersed in p a r a , V.26427, x4. E, small leaf (by transmitted light, transfer preparation), V.25872, x 4. F, small leaf, transfer by transmitted light, V.25878, x 4.

safranine or other stain. The surface of the guard cells shows a very distinct ridge near the aperture, which is thought to represent a wide “vorhof,” and a delicate cuticle extends inwards through the aperture.

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Jurassic Specimens of Sagenopteris. 26 1

The cells next the stomate are as a rule unspecialized, but in some stomates one or more cells are thickened to form papillae which point upwards or else overhang the guard-cell margin. Occasionally also the cell has divided to cut off an unspecialized “encircling cell” from a thickened “ subsidiary cell.”

A peculiar feature is that the cutinized walls of the surrounding epidermal cells extend inwards under the guard cells; this inward extension is developed more strongly in some specimens than others, some merely showing a slight extension of the wall where two sub- sidiary cells meet, others showing the whole extent of the anticlinal walls where they underlie the guard cells.

1. Mesophyl1.-Certain leaves yielded a good deal of resistant internal matter on maceration, but this tends to be granular and did not indicate such definite cells as are seen in S. colpodes. The cells under the upper cuticle (palisade) appear to be rounded and 20 p wide ; no other layer was detected.

2. Petiole.--The cuticle of the petiole shown in fig. 3 F is thicker on one side than the other and shows straight- sided cells in rows ; it differs fiom the specimen figured by Thomas in that the cells are of similar length on the two sides.

3. Small hues.-Three specimens of bract-like leaves were studied, two isolated, one apparently still attached (fig. 5D). They agree in having an expanded base, no distinct petiole, and leaflets with unusually crowded veins. The cuticle (of the basal part) shows the usual straight-sided cells.

Leaves of this sort have been known for a long time ; Halle figured a h e series for S. undulata. The variation in shape of the lamina is noteworthy; it is evidently impossible to distinguish species by the shape of the lamina in these small leaves. The nature of these leaves appears to be an organ formed near the base of a shoot between the bud-scales and foliage leaves. There is no justification for calling them “ young ” leaves as several other authors have done. 4. Bud-scales.-Numerous scales are attached to the

shoot (fig. 5 D) ; two were fairly complete and one was ultimately detached. The bud-scales are oval, 2-3 mm. long with a broad base. They form a concave scale

No hairs were detected.

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262 &. Tom M. Harris on some

bearing at the apex a minute appendage (cf. lamina) with a scarious margin. The substance is thick and the vascular tissue was not made 'out ; the cuticle of the

Fig. 6.

A-E, extreme forms of S. phiZZ6psi ; F-H, normal specimens of S. colpodes, all x 1.

A, longest leaflet known, V.24677. B, undivided leaf, V.25853. D, partly divided leaf (cuneata form),

F, S. colpodes leaf, one leaflet G, 8. colpodes holotype, V.26441.

scale is thick and shows very strongly marked outlines of straight-sided, squarish cells. The cuticle of the apical appendage is thinner; its margin is an extension for

C, undivided leaf, V.26460. V.21401. probably missing, V.21886. H, V.26440.

E, small leaf, V.24676.

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Jurassic Specimens of Sagenopteris. 263

6 0 p of a single layer of cells, partly continuous, partly broken into hair-like portions.

The bud-scale had not hitherto been recognized. 5. Stem.-The only specimen (fig. 5 D) is a moderately

well-preserved shoot bearing at its base one (or two 2 ) side shoots largely concealed by scales. The main shoot shows a conspicuous leaf scar and probably four others which are borne spirally; it is in apparent continuity with a small leaf identified as S. phillipsi by its form and cuticle.

The surface of the stein is marked by more or less conspicuous longitudinal ridges, some of which start from the leaf scars. The best leaf scar is oval, with raised margins and a conspicuous C-shaped print repre- senting a vascular strand; another near the base is broader and less high.

Careful attention was given to the question of the attachment of the Sagenopteris leaf. At certain points no break at all in tissue could be seen ; above this there is a small gap, below overlap by the leaf base. Probably this could have been shown by making a transfer prepara- tion, but the specimen was not risked because it is unique and not my own.

Comparison of S. colpodes, S. phillipsi, and other Species.

The leaf form is variable in all species and there is great overlap between them, though probably S. phillipsi is usually to be distinguished by its narrow and S. colpodes by its broad leaflets. S. undulatu of the Rhaetic (Halle, 1910) is alone well distinguished by its dentate margin.

The cuticles provide a valuable and perhaps the only safe specific criterion. S. colpodes is unique in having sinuous cell-walls in all parts of its leaves and petiole.

S. phillipsi has a cuticle like those of S. undulatu and 8. nilssoniana (Lower Lias, see Harris, 1932), but slight differences exist; 8. undulata has rather less straight- walled cells ; s. nilssoniana (Lower Lias) has a thinner cuticle with very obscure, instead of conspicuous cell outlines.

S. hallei (Lower Lias, see Harris, 1932) is distinguished by the presence of a papilla in the cells of the lower side.

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264 On some Jurassic Specimens of Sagenopteris.

Slight differences in hairiness exist. X. phillipsi is almost perfectly glabrous ; S. colpodes has minute hairs, especially on the petiole ; 8. nilssoniana has better developed hairs on the petiole. Differences of degree exist in the mesophyll and surface sculpture, but are only seen where the preservation is particularly suitable.

GENERAL DISCUSSION. It is noteworthy that the cuticle has made possible

the division of this Sagenopteris material into two sharply defined groups while no macroscopic character would serve. The clearing up of these two species is likely to assist in advancing our knowledge of the reproductive organs.

Two new points have come from the study of the lamina. In S. phillipsi the stomate is interesting in that the guard cells overlap the deeper parts of the surrounding epidermal cells, as they do in many angiosperms, e. g., Helleborus, and are evidently quite different in shape from the prevailing Gymnosperm type. The other is that the mesophyq is sometimes preserved (especially in S. colpodes), where it appears probable that a transfusion mesophyll occurs, comparable to that of various leaves with widely spread veins (Conifers, Cycads, some Monocotyledons, but not in typical Dicotyledons).

The discovery of the stem and bud-scale is of interest and should be of value in identifying future specimens of stems, from which one may hope to learn how the sporophylls were borne.

I wish to thank Mr. W. N. Edwards and M i . 3’. M. Wonnacott for their help in the preparation of this paper, and I am indebted to the Trustees of the British Museum for permission to study the material.

SUMMARY.

1. A series of Sagenopteris leaves from the Oolite of Yorkshire is described.

2. They are shown to consist of two species, S. phillipsi (Brongn.) with straight walled, and 8. colpodes, sp. n., with sinuous epidermal cells. S. philZipsi (Brongn.) includes S. cuneata (L. & H.).

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The North American Genera of Chamzmyiinz. 265

3. Small foliage leaves and scale leaves of each are

4. A small stem of X. phillipsi is described. described.

LITERATURE. BRONUNIART, A. 1828. ‘ Histoire des V6g6taux fossiles,’ xi+488 pp.,

clxi. pls. Park. BUNBWY, C. 3. F. 1851. “ On some Fossil Plants from the Jurassic

Strata of the Yorkshire Coast.” Quart. Journ. Geol. Soc. vii. pp. 179-194, pls. e.-x“‘.

DABRAH, W. C. 1939. Text-book of Paleobotany.’ New York & London.

H~LLE, T. G. 1910. “ On the Swedish Species of Sugenolpteris Presl and on Hydropti?raqium, nov. gen.” I(. Svenska Vet.-Akad. Hand. xlv. 7, pp. 1-16, pls. i.-iii.

HARRIS, T. M. 1932. “ The Fossil Flora of Scoresbx Sound, East Greedand.-3. Caytoniales and Bennettitales. Medd. om Granland, I x x x v . 5, 133 pp., xix. pls.

-. 1933. “ A New Member of the Cavtoniales.” ‘ New Phvto- ~~

logist,’ xxxii. pp. 97-114, pls. iv., v. LINDLEY, J., & EUTTON, W. 1833. ‘ The Fossil Flora of Great

Britain,’ i. li+218 pp., pls. i . - k x . -. ‘ The Fossil Flora of Great Britain,’ ii., xxviii+208 pp., pls. Ixxx.4vi. London.

PHDLIPS, J. 1829. ‘ Illustrations of the Geology of Yorkshire,’ xvi+ 192 pp., xxiii. pls. York.

SEWARD, A. C. 1900. I‘ Notes on some Jurassic Plants in the Man- Chester Museum.” Mem. Proc. Manchester Lit. & Phil. SOC.

London. 1835.

xliv. iii. 8, pp. 1-28, pls. i.-iv.

of Geolopv. British Museum (Natural Historv). -. 1900 a. ‘Catalogue of the Mesozoic Plants in t,he Deparatment

“The Jurassic Flora.-y.” .%‘he Yorkshire Co&t,” xii+341 pi.; xxi. pls.

- . 1910. ‘ Fossil Plants,’ ii. xxi+62$ pp., 265 figs. Cambridge. STERNBERG, C. GRAF VON. 1820-1838. Versuch einer geognostisch-

botanischen Darstellung der‘Flora der Vorwelt,’ i.-viii. Leipzig. THO-, H. HBMSHAW. 1925. The Caytoniales, a New Group

of Angiospennous Plants from the Jurassic Rocks of Yorkshire.” Phil. Trans. Roy. SOC. London, B, ccxiii. pp. 299-363, pls. xi.-xv.

XXI1.-The North American Genera of The Dipterous

TRIs group has usually been given either family status as Ochthiphilidae or considered as a subfamily of Agromy- zidz. I place it as a subfamily of Sciomyzidz along with several others, including the Sapromyzinz.

In 1921 I published a key to the genera, which Curran reproduced with some curtailment and an alteration of sequence in his book on North American Diptera in 1934. In the latter paper Curran has produced a peculiar situation by erecting a new genus for the reception of a

Subfamily Chamzmyiinz. By JOHN R. MALLOCH.

Ann. & Hag. N . Hist. Ser. 11. VoZ. vi. 18

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