Mode Of Branching Research Articles

Studies on Morphological forms of Staphylotrichum Coccosporum

Staphylotrichum coccosporum Meyer & Nicot was described as an inhabitant of tropical soils (3). The authors indicated the variability of the species with reference to minor morphological details, color of cultures, and sporulation on artificial media. Although this is the only report in available literature of this fungus, it is commonly found in soil used in Purdue University greenhouses, usually as much as 5% of the microflora. The species is associated with cellulose decomposition and, with cellulose-amended soil, can be isolated in much larger numbers. The morphology and variability of 86 isolates grown on potatodextrose-agar medium were compared. Several morphological types were distinguished in wild-type cultures. Three mutant types arose in culture media. WILD TYPES. Variation occurs between isolates in: (1) mode of formation of conidial stalks, (2) length of conidial stalks, (3) mode and degree of branching of conidiophores, (4) spore size, (5) color. Conidial stalks may arise on a hard, spherical to ellipsoidal base, averaging 45 X 36 u, distinct from the underlying mycelium (FIG. 1, d, e). Several such units may originate from the same point. In other isolates, conidial stalks are formed in groups (FIG. 1, f, g) or singly. In intermediate types, the underlying mycelium forms more or less compact, sometimes pseudoparenchymatous, masses on which conidial stalks develop. A pore is centrally located at each septum of a conidial stalk (FIG. 1, g). The average length of conidial stalks ranges from 805 to 1182 p, so that short, intermediate, and long-stalked isolates occur (FIG. 1, a, b, c). The fertile part of the conidial stalk is 16 to 21% of the

The morphology of Stauropteris oldhamia Binney

The mode of branching of the frond of Stauropteris oldhamia Binney, previously described up to the rachises of the 4th order (BERTRAND, 1907-9) has now been described up to the minute tips, viz. the rachises of the 5th and 6th orders. The aphlebiae are shown to be branched structures, consisting of up to 13 divisions which arise by fundamentally dichotomous branching. The aphlebial divisions have a fibrous structure and are supplied with minute vascular strands. The morphological nature of the aphlebiae is discussed. In the light of the present findings a new reconstruction of a part of the frond of Stauropteris oldhamia is given.

COMMUNICATIONS BETWEEN THE FACIAL AND TRIGEMINAL NERVES IN CERTAIN MAMMALS

The modes of division and branching of the extrapetrous part of the facial nerve and the presence or absence of communications between its branches and between it and the trigeminal nerve and cervical plexus were studied in nineteen mammalian species. Communications between the facial and derivatives of the mandibular division of the trigeminal were found invariably, but were inconstant in the case of the two other divisions and of the cervical plexus.The possible functional significance of the observations is discussed.

Ramification d'une tige principale de Lyginopteris oldhamia Binney

Abstract Lyginopterids are among the plants preserved in lower and middle Carboniferous coal balls of Great Britain and Germany. The process and mode of branching of stems of Lyginopteris oldhamia are discussed on the basis of a study of serial cross sections.

Developmental morphology of the floral organs of Eucalyptus. I. The inflorescence

The nature and structure of the inflorescenoe of Eucalyptus is re-defined in the light of an analysis of the unit inflorescenoe, its development, mode of branching, bract systems, and the grouping of unit inflorescences into compound inflorescences. The structure of the unit inflorescence in 80 representative species is elucidated and a systematic notation for expressing the numbers and arrangement of the involucral bracts in dichasial inflorescences is proposed. The infloresoence bud of Eucalyptus is generally asymmetrical in side view and often also in face view. External asymmetry is largely a result of the asymmetry of the outermost pair of bracts, by which the developing inner bracts and flowers are at first tightly enclosed, and may be reflected in an asymmetrical pattern of branching within the inflorescence. The asymmetry and pattern of branching are reflections of morphological features peculiar to the shoot system of Eucalyptus. The outer bracts resemble the adult leaves in their asymmetry about the midrib. The leaf and bract primordia arise decussately at the shoot apex but in most species the leaves of each pair become separated by the development of a segment of axis (an "intranode") between them. In certain species the development of an intranode between the outer pair of bracts leads to the splitting apart or "disarticulation" of the unit inflorescence into two subclusters. The very complex inflorescence of E. camaldulensis arises by disarticulation of a simple inflorescence, followed by interpolation, in a centripetal manner, of additional bracts and flowers between those first formed. Flower numbers in clusters at successive nodes of the annual shoot may vary, rising with node number if the inflorescences are basitonically disposed, falling if acrotonically disposed. Flower number in successive clusters is correlated with other quantitative features of the annual shoot. The position and number of the inflorescenoe buds on the annual shoot and the interval between flower initiation and anthesis are characteristic of species and of groups of species. Phylogenetic trends in inflorescence characters are discussed. Inflorescences with few flowers and with free persistent bracts, the number of which is related to the flower number in the cluster, are held to be primitive. Inflorescences with many flowers, fused bracts constituting a caducous involucre in which the number of bracts is not related to the number of flowers, are held to be advanced. These and other charaoters of the infloresoence are shown to have taxonomic significance and their use is typified in an analysis of the infloresoence characters of the Renantheroideae in relation to those of the Renantherae.

Studies on the Autonomic Nervous Terminations in the Alimentary Tract of a Cat

A study was made of features of the terminations of vegetative nerve-fibres using the alimentary tubes of adult cats. The specimens observed were impregnated by SUZUKI's silver-method after they were made into frozen sections. The results summarized in the following description are derived from the data regarding the muscle-layer of colon and the mucous layer of stomach.1. According to the mode of branching, the nerve networks of AUERBACH's plexus can be classified into 5 orders. The network of the 5th order are composed of mere neurofibrils from which fine terminal nerve-fibres come out between smooth muscle fibres. From this finding, it became evident that the nerve-fibres of AUERBACH's plexus innervated the muscle fibres in both circular and longitudinal plates of the muscle-layer of colon.2. Bundles of nerve-fibres in the alimentary tract are accompanied by the following cells or nuclei, i. e., ganglion-cells, nuclei in leitplasmodium, and intercalated cells. They seem to be innervated in conformity with the function of respective organs.3. Of a neurofibrilar structure of peripheral nerve-fibres there exist four basic types as follows:a. Fibres composed of dense neurofibrils with very few anastomosis.b. Fibres composed of thin neurofibrils with many dot-like swellings and few anastomosis.c. Fibres composed of thin neurofibrils with varicosity.d. Fibres composed of thin reticulum of neurofibrils with dot-like swellings.4. The nerve-cells in MEISSNER's plexus of colon are very often located in groups and occasionally they are found enveloping the ganglion.5. Bundles of neurofibrils passing through the lamina muscularis mucosae of stomach contain three kinds of neurofibrils as follows:a. The bundle which independently passes through the muscle-plate, and while sending out fine branches on its passage.b. The bundle which finds its way with a thin longitudinal bundle of smooth muscle fibres in the mucous layer after forming a network in the innermost part of lamina muscularis.c. The bundle which passes through lamina muscularis with blood capillaries.6. In the interspace between the cell-basis and the proper membrane of a fundic gland there exists a fine meshed reticulum of neurofibrils from which very delicate neurofibrils come out ending between gland cells. Intercalated cells are also found in some parts of the gastric glands. Their cytoplasma, which are filled with fine argyrophilic reticula, come from the above mentioned basal reticula which send forth thin processes around adjacent gland cells.

CXVIII.—The mode of branching in the early history of Tetrapods

CXVIII.—The mode of branching in the early history of Tetrapods

VI.—The Heart and Great Vessels in the Strepsirhini

SynopsisDetails of the anatomy of the heart and the great vessels are recorded in the following genera of prosimian Primates,Loris, Arctocebus, Perodicticus, Galago, Galagoides, Hapalemur, Lemur, LepilemurandPropithecus, and comparison made with previously published data onNycticebus. Special attention is drawn to the proportions, shape and mode of branching of the systemic aorta, which is of typical lemurine pattern in all butLorisandPropithecus. In the heart, attention is paid particularly to the valvular arrangements in the right atrium, where much variation has been found; to the number of pulmonary veins entering the left atrium, also a variable feature; to the internal and external morphology of the ventricles and the valvular arrangements therein. The presence of an os cordis is recorded for the first time in any Primate (viz. inLoris), and the occurrence is mentioned of “brown” (glandular) fat sub-epicardially inLoris. The significance is discussed of the principal anatomical features.

A study of the branched cells of the mammalian epidermis with special reference to the fate of their division products

The branched cells of the superficial epidermis of mammals are divisible into two classes: those that occupy a position in the basal layer, and those that occur in more superficial layers. The first class comprises melanocytes visible in the living epidermis after its enzymatic fission from the corium; cells that blacken upon exposure to dihydroxyphenylalanine; cells that maintain quinoneimine dyes in the oxidized state in living skin; and clear cells. It is shown that these are merely different preparation images of the same cell, the melanocyte. The second class comprises cells that may be more or less specifically impregnated by metallic gold (Langerhans’ cells); cells stainable in living skin by quinone-imine dyes; and the ‘clear cells’ of superficial strata. It is shown that these, too, are so many preparation images of the same cell. It is argued that the branched cells of superficial strata, which have never been seen to divide, represent effete melanocytes which, having discharged or otherwise lost their pigment, participate in the general outward movement of epidermal cells to be cast off at the skin surface. This argument is supported by evidence of their similarity of structure, mode of branching, and relationship to neighbouring Malpighian cells; by their position in the epidermis; by their one-to-one correspondence of number; and by their coincidence of distribution.

THE RÔLE OF THE FIN RAYS IN THE REGENERATION IN THE TAIL-FINS OF FISHES

1. Regeneration is faster from the level of the cut that exposes more fin-ray cross surface. The difference in arrangement of the fin rays in the tails of Fundulus and goldfish accounts for the rate of growth being faster or slower at opposite regions of the two types of tails.2. Regeneration from square holes cut in the tails of fishes shows that a reversal of growth of the rays from the posterior face of the hole is possible. Healing in the longitudinal faces and repairing of the injured rays take place. Regeneration takes place only from the cross-cut ends of fin rays. The reversed rays are of the same branching pattern as the distal portion from which they are produced; that is, the same pattern that a cross cut would regenerate posteriorly from that level.3. When rays that normally would grow into the lobe of the tail are displaced into the central portion of the tail of a goldfish, they are not "held back" by any tension in the center of the tail. The rays continue to grow and form abnormal lobes in the central portion of the tail.4. Correlation between size and branching is brought out by two types of cuts. (a) A cut surface anterior to the scaly base of the tail in Fundulus regenerates "abnormal" rays. The shape of the tail can thus be changed from rounded to straight, and persists as such for more than seven months. (b) An oblique cut at the point of doubling of rays in the goldfish exposes more cross surface than a straight cross cut. The regenerate from such a surface has produced a third set of branches instead of two sets, as would be typical in the goldfish used.5. There is a minimum size of all rays in a particular kind of tail, and the size is apparently equal for all the rays.6. The evidence herein presented suggests that the fin rays are self-differentiating structures.(a) The initiation of growth is due to cutting the fin rays crosswise.(b) Rate of growth seems to depend on the amount of exposed surface of the fin rays.(c) Cessation of growth appears to be due to the attainment of the minimum size of the ray at which no further growth takes place.(d) Form of the tail appears not to be associated with pressure or tension relations but with the mode of branching of the fin rays and hence their size and the formative influences that they possess.

Odontocaulis Lapworth, a synonym of Callograptus Hall

The original generic diagnosis is as follows:—“Polypary cyathiform, composed of numerous independent and frequently bifurcating polypiferous branches, originating from the distal extremity of a short stem, which is likewise polypiferous and is terminated proximally in an irregular corneous expansion. Hydrothecae of the type of those of Dictyonema, biserial, sub-alternate.“The chief peculiarity of this genus is afforded by the character of the stem, which is identical in every respect with the main branches, and, like them, is denticulate or polypiferous throughout the whole of its extent. It commences proximally in a flattened expansion, with irregular or frayed-out edges, possibly the remains of a disk or bulb of attachment.“The mode of branching is rigidly dichotomous, the first two branches being formed by the sub-division of the main stem itself. Each arm branches and rebranches again and again in the same manner, at frequent and close intervals, composing an elegant cyathiform or fan-like polypary, very symmetrical in form. The branches retain their original width to their final division, which gives rise to two minute branches less than one-tenth of an inch in length.

XIX.—Contributions to the Study of the Old Red Sandstone Flora of Scotland. VI. On Zosterophyllum myretonianum, Penh., and Some Other Plant-remains from the Carmyllie Beds of the Lower Old Red Sandstone. VII. On a Specimen of Pseudosporochnus from the Stromness Beds

Among the commonest and most abundant plant-remains in the Carmyllie and Cairnconon Beds of the Caledonian Lower Old Red Sandstone are branched linear axes about 2 mm. in width. These often occur in a fragmentary condition, but more connected portions demonstrating the morphology of the plant are also found. Though often associated with Parka and Nematophyton, the plant known as Zosterophyllum myretonianum is usually readily recognisable by its definite outline and uniform diameter, by its modes of branching, and by the remains of structure which it sometimes retains. As will be seen below, the axis of this plant was traversed by a single median strand that was composed of tracheides. Zosterophyllum is thus of special interest as the most ancient vascular plant known from British rocks. Some other plant-remains that may be confused with it have also been met with, though less commonly. These will be briefly considered, not merely for this reason, but on account of the very different and peculiar type of structure they exhibit.

Development of Head and Flower of Dipsacus sylvestris

1. The mode of branching is uniform for each individual plant. 2. New branches arise from the axils of clasping leaves. 3. The capitulum, or floral head, which terminates each branch is the first to make its appearance in the development of a branch. 4. The primordia of the bracts forming the involucre of the capitulum appear early, followed quickly by the initials of clasping leaves. 5. A twofold region of elongation sets in immediately above and below the initials of the clasping leaves of the new branch. 6. Secondary branches appear very early in the axils of the leaves clasping new branches. 7. The initials of the floral bracts appear before the papillae of the individual flowers, which they subtend. 8. The flowers are arranged in the form of a spiral. 9. The order of succession of floral members is corolla, stamens, calyx, and carpels, the calyx appearing almost simultaneously with the stamens. 10. The initials of a calyx-like involucel investing the ovary appear shortly after the initials of the calyx.

Scientific Serials

THE Quarterly Journal of Microscopical Science for March contains:—On a new species of Phymosoma, with a synopsis of the genus, and some account of its geographical distribution, by Arthur E. Shipley (Plate xi.). The new species, P. weldoni, was found by Prof. Weldon at Bimini Island, the Bahamas; it has no trace of hooks on the introvert; there are two retractors. A synopsis of the twenty-seven species now known is given, but seventeen species are described in Selenka's monograph on the Sipunculidæ. As to the geographical distribution, seventeen species are found in the Malay Archipelago, of which thirteen are endemic, five are found in the Red Sea, four in the Mauritius, and three are found in the West Indies, but P. lovenii is found only in the Bergen Fiord.—On the British species of Crisia, by Sidney F. Harmer (Plate xii.). The author thinks that the ovicells furnish satisfactory specific characters; the aperture in the ovicell is also an important character. Specific diagnoses of C. denticulate, Lmk., C. eburnea, Linn., C. aculeata, Hass., and C. ramosa, n. sp., are given. Notes are given of the habit of the Zoarium at different seasons, on the mode of branching, and on the breeding-times.—The later larval development of Amphioxus, by Arthur Willey (Plates xiii.-xv.). The author again visited Messina, in the summer of 1890, to complete his studies on the development of the atrial chamber of Amphioxus. As a possible explanation of the asymmetry of the larva, Willey thinks that it can be traced ultimately to the adaptive forward extension of the notochord, being thus a purely ontogenetic phenomenon; the club-shaped gland is shown to be a modified gill-slit. —On the structure of two new genera of earthworms belonging to the Eudrilidæ, and some remarks on Nemertodrilus, by Frank E. Beddard (Plates xvi.-xx.). Hyperioadrilus africanus, n. gen. and sp., and Heliodrilus lagosensis, n. gen. and sp., found in a Ward case from Lagos, at Kew Gardens.

XXXII.—Note on Ectocarpus

The group of the Phæosporeæ was first recognised by Thuret in 1850. It includes algæ that vary greatly in size, habit, external appearance, and mode of branching, some possessing a flat thalloid appearance with or without a long stalk (e.g., Laminariæ), others being filamentous and much branched (e.g., Ectocarpus, Sphacelaria, Chordaria, &c). The great majority of the genera included in the group are marine or brackish water forms, but recently E. Flahault has described, under the name of Lithoderma fontanum, a fresh water species from the neighbourhood of Montpellier.

Thamniscus : Permian, Carboniferous, and Silurian

The genus Thamniscus was founded in 1849 by Prof. King for a Polyzoan of large size found in the Permian beds of the north of England. The main interest of the genus consisted in Prof. King claiming for the type species the possession of certain “denticles,” “vesicles,” and “hemispherical bodies” similar to those observed in “certain Lunulites and Cellaria salicornia ”. Prof. King further institutes comparisons between these peculiarities in his genus and some of the recent forms of Polyzoa formerly included among Elasmopora, Escharina , and Cellepora . It is needless to say that these features at once assign the genus to the order of Chilostomatous Polyzoa; and as such it is entitled to rank as the most pronounced type of its class found among the Palæozoic Polyzoa. How far these characters can be sustained will be the subject of after inquiry. The next reference to the genus that I find is in 1874, when Mr. R. Etheridge, Jun., described, as found in some Scottish Carboniferous Limestone shale, a fragment of a Polyzoan which he thought might be a new species of Polypora , at the same time remarking that the disposition of the cells and the mode of branching were exceedingly like those seen in the type species of Thamniscus ( T. dubius , King), and suggesting that it might be a species of that genus.

I.—On the Microscopic Structure of Three Species of the Genus Cladochonus, M‘Coy

1. History.—The genus Cladochonus was founded by Prof. M'Coy in 1847 (Annals Nat. Hist. vol. xx. p. 227) for certain Australian Palæozoic corals with “some relation to Aulopora,” but differing “in their curious erect habit, regular, angular mode of branching, slender, equal stem-like tubes, and abruptly dilated terminal cups bent in nearly opposite directions.”Prof. M'Coy also lays stress upon the thickness of the walls in Cladochonus, and the proportionately small calices, and states (loc. cit., and Ibid. 1849, vol. iii. p. 134) that the curious little corals formerly referred by him to Lamouroux's Jania will fall into this genus, viz. Jania crassa, and Jania bacillaria (Synop. Carb. Limestone Foss. Ireland, 1844, p.197). The Australian species Cladochonus tenuicollis is distinguished by the slenderness of the stolons connecting the calices. In 1851 Messrs. Milne-Edwards and Haime described a genus under the name of Pyrgia (Polyp. Foss. Terr. Pal. p. 310). which has been placed by subsequent writers as a synonym of Cladochnons, and we think with good reason. To their genus they assign the following characters—the corallum is free, pedicellate, with a strong epitheca, very deep calices, and without traces of septal striæ, and they consider that it differs from Aulopora in its simple and free habit. Two species were described, Pyrgia Michelini, Ed. and H., and P. Labechei, Ed. and H. The Janiæ of M'Coy they reserve their opinion on, but C. tenuicollis of the same authour is referred by them to the young of the genus Syringopora (loc. cit. p. 296). Similar views were expressed by them in their subsequent “Monograph of the British Fossil Corals” (pt. 3, Corals from the Perm. Form. and Mounatain Limset. p. 164). 1 and they further describe their Pygria Labechei (loc. cit. p. 166).

I.—On Halonia of Lindley and Hutton and Cyclocladia of Goldenberg

The genus Halonia was established in the Fossil Flora (vol. ii., p. 13) by Lindley and Hutton for those fossils in which, to the surface of Lepidodendron, is added the mode of branching of certain Coniferœ, and which were therefore inferred to be of a nature analogous to the latter. It was assumed that Lepidodendron, being an extinct form of Lycopodiaceœ, must be limited to the fossils in which the branching was dichotomous, since no other kind of branching is met with in recent Lycopodiaceœ. But when we look at such plants as Lycopodium cernuum and L. densum, we find branching precisely similar to that in Halonia gracilis, L. and H.; and whether these were produced or not by the division of a terminal bud, it is certain that in their developed condition they are arranged in an alternate manner round a common elongated axis— a plan of branching characteristic, as the authors of the Fossil Flora supposed, of Coniferœ.

XII. On the apparent relation of the nerves to the muscular structures in the aquatic larva of Tipula crystallina of de geer

To avoid as much as possible errors that might be attributable to a faulty mode of examination, the figures and photographs have all been made from the larvæ alive, and in their natural medium, except two instances in the drawings and one in the photographs. After alluding to the effects of various reagents which were generally found useless in “differentiating” the fine nervous structures, and the ordinary mode of branching in the nerves from the ganglionic chain, two particular methods of termination are selected as illustrative of the relation between the muscular and nervous tissues. One, termed the “flabelliform,’’ where the nerve on approaching the muscular sheath expands into a fan shape, and with its fine granular and nucleated contents embraces the muscle in form of the letter A, without any evidence of the granulai matter and sarcous elements being in absolute contact; the other, called the “stapiform” or stirrup-shaped. The latter, in its early stage, is knobbed in appearance. This, the early stage, is shown gra­dually passing into the cellular, looped, or stirrup form, embracing the fine muscular structure somewhat obliquely, or passing entirely round it, and projecting beyond its edge. In this form also there was no evidence of any union of the granular contents with the sarcous elements, though firm union existed between their sheaths or outer membranes. Fine networks, ending apparently in a granular irregular spot with a pale centre and uniting, are pointed out. The relation and union of short muscles passing between others, and nerve-fibres lying along­ side them, with flabelliform expansions, are remarked on, and shown in the figures and photographs. Muscles undergoing degeneration, or the metamorphic change, are noticed, and in no instance could a nerve-fibre be seen attached to them, or a fibre that could with certainty be traced to any nerve or ganglion. No change was observed of a definite character, as regards the mode of union, under muscular contraction. Some of the finest muscular fibres are passed by for special reasons, as constant motion &c. Attention is called to the blood-corpuscles, or to corpuscles which, for convenience, are called creeping corpuscles, and several figures given. The peculiarities of these bodies are regarded as of consi­derable importance, and, coupled with a remark in Dr. Beale’s contri­bution to the Transactions of the Royal Society, read May 21st, 1863, in reference to the movement of all forms of living matter.

On the mode of branching of some Amazon trees.

On the mode of branching of some Amazon trees.