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Ancient Plants / Being a Simple Account of the past Vegetation of the Earth and of the Recent Important Discoveries Made in This Realm of Nature cover

Ancient Plants / Being a Simple Account of the past Vegetation of the Earth and of the Recent Important Discoveries Made in This Realm of Nature

Chapter 28: INDEX
By Marie Carmichael Stopes
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About This Book

This work presents a concise, non-technical survey of the earth's past vegetation, explaining types of fossil plants and coal formation, outlining seven geological plant ages and stages in plant evolution. It compares fine anatomical details of fossil and living plants, notes likenesses and differences, and traces past histories of major groups—flowering plants, gymnosperms, bennettitales, cycads, pteridosperms, ferns, lycopods, horsetails, sphenophyllales, and lower plants. The volume emphasizes how fossils reconstruct ancient landscapes and climates and includes practical guidance on collecting and preserving specimens and a glossary of technical terms.

GLOSSARY

Some of the more technical terms about which there might be some doubt, as they are not always accompanied by explanations in the text, are here briefly defined.

Anatomy.—The study of the details and relative arrangements of the internal features of plants; in particular, the relations of the different tissue systems.

Bracts.—Organs of the nature of leaves, though not usual foliage leaves. They often surround fructifications, and are generally brown and scaly, though they may be brightly coloured or merely green.

Calcareous.—Containing earthy carbonates, particularly calcium carbonate (chalk).

Cambium.—Narrow living cells, which are constantly dividing and giving rise to new tissues (see fig. 33, p. 57).

Carbonates, as used in this book, refer to the combinations of some earthy mineral, such as calcium or magnesium, combined with carbonic acid gas and oxygen, formula CaCO3, MgCO3, &c.

Carpel.—The closed structure covering the seeds which grow attached to it. The “husk” of a peapod is a carpel.

Cell.—The unit of a plant body. Fundamentally a mass of living protoplasm with its nucleus, surrounded in most cases by a wall. Mature cells show many varieties of shape and organization. See Chapter VI, p. 54.

Centrifugal.—Wood or other tissues developed away from the centre of the stem. See fig. 65, p. 97.

Centripetal.—Wood or other tissues developed towards the centre of the stem. See fig. 65, p. 97.

Chloroplast.—The microscopic coloured masses, usually round, green bodies, in the cells of plants which are actively assimilating.

Coal Balls.—Masses of carbonate of calcium, magnesium, &c., generally of roundish form, which are found embedded in the coal, and contain petrified plant tissues. See p. 28.

Concretions.—Roundish mineral masses, formed in concentric layers, like the coats of an onion. See p. 27.

Cotyledons.—The first leaves of an embryo. In many cases packed with food and filling the seed. See fig. 58.

Cross Fertilization.—The fusion of male and female cells from different plants.

Cuticle.—A skin of a special chemical nature which forms on the outer wall of the epidermis cells. See p. 54, fig. 21.

Earth Movements.—The gradual shifting of the level of the land, and the bending and contortions of rocks which result from the slow shrinking of the earth’s surface, and give rise to earthquakes and volcanic action.

Embryo.—The very young plant, sometimes consisting of only a few delicate cells, which results from the divisions of the fertilized egg cell. The embryo is an essential part of modern seeds, and often fills the whole seed, as in a bean, where the two fleshy masses filling it are the two first leaves of the embryo. See fig. 58, p. 77.

Endodermis.—The specialized layer of cells forming a sheath round the vascular tissue. See p. 55.

Endosperm.—The many-celled tissue which fills the large “spore” in the Gymnosperm seed, into which the embryo finally grows. See fig. 57.

Epidermis.—Outer layer of cells, which forms a skin, in the multicellular plants. See fig. 21, p. 54.

Fruit.—Essentially consisting of a seed or seeds, enclosed in some surrounding tissues, which may be only those of the carpel, or may also be other parts of the flower fused to it. Thus a peapod is a fruit, containing the peas, which are seeds.

Gannister.—A very hard, gritty rock found below some coal seams. See p. 25.

Genus.—A small group within a family which includes all the plants very like each other, to which are all given the same “surname”; e.g. Pinus montana, Pinus sylvestris, Pinus Pinaster, &c. &c., are all members of the genus Pinus, and would be called “pine trees” in general (see “Species”).

Hyphæ.—The delicate elongated cells of Fungi.

Molecule.—The group of chemical elements, in a definite proportion, which is the basis of any compound substance; e.g. two atoms of hydrogen and one atom of oxygen form a molecule of water, H2O. A lime carbonate molecule (see definition of “Carbonate”) is represented as CaCO3.

Monostelic.—A type of stem that contains only one stele.

Morphology.—The study of the features of plants, their shapes and relations, and the theories regarding the origin of the organs.

Nucellus.—The tissue in a Gymnosperm seed in which the large “spore” develops. See figs. 55 and 56, p. 76.

Nucleus.—The more compact mass of protoplasm in the centre of each living cell, which controls its growth and division. See fig. 17, n.

Palæobotany.—The study of fossil plants.

Palæontology.—The study of fossil organisms, both plants and animals.

Petiole.—The stalk of a leaf, which attaches it to the stem.

Phloem.—Commonly called “bast”. The elongated vessel-like cells which conduct the manufactured food. See p. 57.

Pollen Chamber.—The cavity inside a Gymnosperm seed in which the pollen grains rest for some time before giving out the male cells which fertilize the egg-cell in the seed. See p. 76.

Polystelic.—A type of stem that appears, in any transverse section, to contain several steles. See note on the use of the word on p. 63.

Protoplasm.—The colourless, constantly moving mass of finely granulated, jelly-like substance, which is the essentially living part of both plants and animals.

Rock.—Used by a geologist for all kinds of earth layers. Clay, and even gravel, are “rocks” in a geological sense.

Roof, of a coal seam. The layers of rock—usually shale, limestone, or sandstone—which lie just above the coal. See p. 24.

Sclerenchyma.—Cells with very thick walls, specially modified for strengthening the tissues. See fig. 28, p. 56.

Seed.—Essentially consisting of a young embryo and the tissues round it, which are enclosed in a double coat. See definition of “Fruit”.

Shale.—A fine-grained soft rock, formed of dried and pressed mud or silt, which tends to split into thin sheets, on the surface of which fossils are often found.

Species.—Individuals which in all essentials are identical are said to be of the same species. As there are many variations which are not essential, it is sometimes far from easy to draw the boundary between actual species. The specific name comes after that of the genus, e.g. Pinus montana is a species of the genus Pinus, as is also Pinus sylvestris. See “Genus”.

Sporangium.—The saclike case which contains the spores. See figs. 52 and 53, p. 75.

Spore.—A single cell (generally protected by a cell wall) which has the power of germinating and reproducing the plant of which it is the reproductive body. See p. 75.

Sporophyll.—A leaf or part of a leaf which bears spores or seeds, and which may be much or little modified.

Stele.—A strand of vascular tissue completely enclosed in an endodermis. See p. 62.

Stigma.—A special protuberance of the carpel in flowering plants which catches the pollen grains.

Stomates.—Breathing pores in the epidermis, which form as a space between two curved liplike cells. See fig. 23, p. 54.

Tetrads.—Groups of four cells which develop by the division of a single cell called the “mother cell”. Spores and pollen grains are nearly always formed in this way. See p. 75.

Tracheid.—A cell specially modified for conducting or storing of water, often much elongated. The long wood cells of Ferns and Gymnosperms are tracheids.

Underclay.—The fine clay found immediately below some coal seams. See p. 24.

Vascular Tissue.—The elongated cells which are specialized for conduction of water and semifluid foodstuffs.

FOOTNOTES

[1]My book was entirely written before the second edition of Scott’s Studies appeared, which, had it been available, would have tempted me to escape some of the labour several of the chapters of this little book involved.
[2]The student would do well to read up the general geology of this very interesting subject. Such books as Lyell’s Principles of Geology, Geikie’s textbooks, and many others, provide information about the process of “mountain building” on which the form of our coalfields depends. A good elementary account is to be found in Watt’s Geology for Beginners, p. 96 et seq.
[3]See note on p. 28.
[4]This refers only to the “coal-ball”-bearing seams; there are many other coals which have certainly collected in other ways. See Stopes & Watson, Appendix, p. 187.
[5]For a detailed list of the strata refer to Watts, p. 219 (see Appendix).
[6]Though the Angiosperm was not then evolved, the Gymnosperm stem has distinct vascular bundles arranged as are those of the Angiosperm, the difference here lies in the type of wood cells.
[7]The gametophyte generation (represented in the ferns by the prothallium on which the sexual organs develop) alternates with the large, leafy sporophyte. Refer to Scott’s volume on Flowerless Plants (see Appendix) for an account of this alternation of generations.
[8]Material recently obtained by the author and Dr. Fujii in Japan does contain some true petrifactions of Angiosperms and other plant debris. The account of these discoveries has not yet been published.
[9]A fuller account of the Angiospermic flora can be had in French, in M. Laurent’s paper in Progressus Rei Botanicæ. See Appendix for reference.
[10]From the Cretaceous deposits of North America several fossil forms (Brachyphyllum, Protodammara) are described which show clear affinities with the family as it is now constituted. (See Hollick and Jeffrey; reference in the Appendix.)
[11]The addition of -oxylon to the generic name of any living type indicates that we are dealing with a fossil which closely resembles the living type so far as we have information from the petrified material.
[12]See reference in the Appendix to this richly illustrated volume.
[13]For fuller description of this interesting cone, see Scott’s Studies, p. 114 et seq.
[14]A brackish swampy land is physiologically dry, as the plants cannot use the water. See Warming’s Oecology of Plants, English edition, for a detailed account of such conditions. For a simple account see Stopes’ The Study of Plant Life, p. 170.
[15]The student interested in this special flora should refer to Arber’s British Museum Catalogue of the Fossil Plants of the Glossopteris Flora.

INDEX

(Italicized numbers refer to illustrations)

Abietineæ, 88, 89, 90.
— family characters of, 91.
Algæ, 44, 47, 165.
— brown, 166.
— green, 165.
— red, 165.
Alnus, 85.
Amber, 17.
Amentiferæ, 84.
Anatomy of fossil plants, likeness in detail to that of living plants, 53 et seq.
— — — — differences in detail from that of living plants, 69 et seq.
Andromeda, 84.
Angiosperms, comparison with Bennettitales, 103.
— early history of, 79 et seq.
— general distribution of in time, 177.
— later evolution of, 178.
— male cell of, 52.
Araliaceæ, 85.
Araucareæ, 88, 90, 111.
— description of, 90.
— primitive characters of, 89.
Araucarioxylon, 93, 95.
Arber, 173.
Archæocalamites, 152.
Artocarpaceæ, 85.
Asterochlaena, 126, 127, 86, 89.
Bacillus, 167.
Bacteria, 167.
Baiera, 101.
Bast, 57, 32.
Bennettitales, 44, 102, 131.
— general distribution of in time, 177.
Bennettites, 103 et seq.
— external appearance of, 103.
— flower-like nature of fructification, 108.
— fructification of, 104, 71, 105, 72.
— seed of, 106, 73.
Bertrand, 2.
Betula, 85.
Bignonia, 84.
Botryopterideæ, 125, 132.
— description of group, 125.
— fructifications of, 128.
— petioles of, 127, 89.
— stem anatomy of, 126, 86, 87.
— wood of, 128, 90.
Botryopteris, 126, 127.
— axis with petiole, 127, 88, 89.
Bowmanites Römeri, 158, 160.
Brachyphyllum, 89.
Brongniart, 2.
Bryophytes, 163.
Calamites, 147, 154, 157, 159, 160, 171.
— branch of, 147, 104.
— casheana, 152.
— cone of, 150, 109, 151, 110.
— leaf of, 149, 107.
— node of, 149, 106.
— spores of, 152, 111.
— young roots of, 150, 108.
— young stem of, 148, 105.
Cambium, 57, 33, 65, 43, 66, 44.
Carbon, film of representing decayed plant, 12.
Carbonate of magnesium, 20.
Carbonates of lime, 19.
Carpels, modified leaves, 78.
Carruthers, 186.
Casts of fossil plants, 8, 9, 2, 10, 3, 4, 11, 12.
— of seeds, 11, 12.
— treatment of specimens of, 184.
Casuarina, 83.
Cells, similarity of living and fossil types of, 53.
— principal types of, 53 et seq., 22-33.
Cell wall, 47, 17.
Centrifugal wood, 97, 65.
Centripetal wood, 97, 65, 116.
Chara, 16.
Characeæ, 163.
Cheirostrobus, 159, 118, 160.
Chloroplast, 47, 17.
Coal, origin of, 29 et seq.
— of different ages, 33.
— seams in the rocks, 24, 13, 14.
— vegetable nature of, 25 et seq.
— importance of, 17, Chap. III, p. 22 et seq.
“Coal balls”, 18, 19, 10, 20, 21, 22, 27, 15, 163, 185.
— — mass of, in coal, 28, 16.
Coal Measures, climate of, 172.
Companion cells, 57, 32.
Concretions, 21, 22, 27, 15, 28.
— concentric banding in, 27, 15.
Conducting tissue in higher plants, 49, 19, 50, 20.
Coniferales, conflicting observations among, 46.
— general distribution in time, 177.
— male cell of, 52.
Corallina, 166.
Cordaiteæ, 39-88, 112.
— comparison of fructifications with those of Taxeæ, 95.
— description of family, 92.
— general distribution in time, 177.
Cordaites, 40, 107, 176.
— fructification of, 95, 96, 64.
— internal cast of stem, 10, 4, 93, 94, 95.
— leaves of, once considered to be Monocotyledons, 82, 93.
— leaves of, 93, 61, 94, 62A.
— possible common origin with Ginkgo, 102.
— wood of, 94, 62B.
Cork, 56, 29.
— cambium, 56, 29.
Cross fertilization, 179.
Cupresseæ, 88, 90.
— description of, 91.
Cycadeoidea, 103.
Cycads in the Mesozoic period, 40, 41, 42, 113.
— description of group, 109.
— general distribution of in time, 177.
— in Tertiary period, 85.
— large size of male cones of, 110.
— seeds of, 112.
— type of seed of, 76, 57.
— wood of, 110.
Cycas, 109, 110, 74.
— seed-bearing sporophyll of, 111.
— seeds of, 112, 76.
— comparison with Ginkgo seeds, 112.
Darwin, 181.
Diatoms, 167, 121.
Dicotyledons, 41, 44, 79.
— relative antiquity of, 81, 82.
— seed type of, 77, 58.
Differentiation, commencement of in simple plants, 48.
— of tissues in higher plants, 49, 19, 50 et seq., 20.
Embryo of Ginkgo, 100.
— in seeds, 76, 57, 77, 58.
— of Bennettites, 106, 73.
Endodermis, 55, 26, 61.
Environment, 181, 182.
Epidermal tissues, 54, 21, 22, 23, 125.
Epidermis cells, fossil impressions of, 13, 14, 8, 59, 34, 125.
Equisetales, 44.
— general distribution of in time, 177.
Equisetites, 146, 103.
Equisetum, 9, 38, 40, 44, 145, 149, 152.
— underground rhizomes of, 43.
Eucalyptus, 83.
Europe, 87, 102.
— ancient climates of, 170.
Evolution, 43.
— in plants, various degrees of in the organs of the same plant, 45 et seq.
Evolution in plants, cause of, 181.
— — — suggestions as to possible future lines of, 178.
Expedition, requirements for collecting, 183.
Extinct families, 44.
Ferns, sporangia of, 67, 45.
— connection with Pteridosperms, 123.
— description of group, 124.
— fructifications of among fossils, 131, 132, 92.
— general distribution of in time, 177.
— germinating spores of, 68, 47.
Ficus, 83.
Flotsam, 6.
Flowering plant, anatomy of stem, 49, 19.
Formation of rocks, key to processes, 6.
Fossil plants, indications of ancient climates and conditions, 168.
— — diagram illustration the distribution of, 177, 122.
Fungi, fossils of, 164.
— parasitic, 119, 164, 165, 120.
Gamopetalæ, 84.
Gannister, 25, 14.
Geikie, 186.
Ginkgo, leaf impression, 14, 7, 100, 69.
— comparison with Cycas seeds, 112.
— distribution in the past, 168.
— embryo of, 100.
— epidermis of fossil, 14, 8, 100.
— foliage of, 99, 66.
— only living species of genus, 98, 70.
— possible common origin with Cordaites, 102.
— ripe seed of, 99, 67.
— section of seed of, 100, 68.
— seed structure of, 76, 57.
— similarity to Cordaites, 96.
Ginkgoaceæ, 88.
Ginkgoales, 88, 98.
— description of group, 98.
— general distribution in time, 177.
Glacial epoch, 170.
Glossopteris, 173.
Glyptostrobus, 86.
Gondwanaland, 173.
Grand’Eury, 186.
Gum, 17.
Gymnosperms, 38, 41, 44, 86, 176, 179.
— connection with Pteridosperms, 124.
— general distribution in time, 177.
— relations between the groups of, 88, 89, 90.
Hairs, 54, 22, 70.
— special forms among fossils, 70.
Heterangium, 119, 122, 123, 127.
— foliage of, 120.
— stem of, 120, 81.
Hollick and Jeffrey, 89.
Horsetails, description of group, 145.
Hutton, 2.
Impression, form of fossil, 5, 12, 13, 6, 14, 7, 15, 80, 81, 59, 60.
— treatment of specimens of, 184.
Investigators of fossil plants, 2.
Iron sulphide, 20.
Jet, 17.
Juglandaceæ, 83.
Kauri pine, 93.
Kew Gardens, 98.
Kidston, 186.
Labelling of specimens, 185.
Lagenostoma, 76, 56, 118, 119, 80.
Laminaria, 166.
Lapworth, 186.
Latex cells, 55, 27.
Lauraceæ, 85.
Laurent, 186.
Leaves, starch manufacture in cells of, 58.
— fossil leaf anatomy, 59, 34.
— general similarity of living and fossil, 58.
Lepidocarpon, 141, 100.
Lepidodendron, 9, 10, 3, 21, 12, 67, 46, 72, 75, 134, 144, 145, 157, 160, 171.
— anatomy of stem of, 136, 137, 95, 138, 96, 139, 97.
— comparison of reproductive organs with those of living lycopods, 67, 46.
Lepidodendron, description of, 134.
— distribution in the past, 177.
— fructification of, 139, 140, 98, 141, 99.
— huge stumps of, 134, frontispiece.
— leaf bases, 10, 3, 135, 93.
— leaf traces of, 139, 97.
— peculiar fructification of, 75, 54.
— petrifaction of leaves, 21, 12.
— rootlike organs of, 69.
— secondary thickening in, 70, 48, 71, 49.
— selaginoides, stem of, 137, 95.
— wood of, 70, 48, 71, 49.
Liliaceæ, 82.
Limestone, 7, 1, 24, 25, 36.
Lindley, 2, 186.
Literature on fossil plants, 186.
Lithothamnion, 166.
Liverworts, 163.
Lycopods, 38, 40, 42, 44, 67, 133, 175.
— description of group, 133.
— general distribution in time, 177.
— reproductive organs of, 67, 46.
— secondary wood in fossil, 70, 48, 71, 49.
Lyell, 186.
Lyginodendron, 115, 116, 122.
— anatomy of stem of, 116, 78A.
— petioles of, 117, 118, 79.
— roots of, 117, 78B.
— seeds of, 118, 119, 80.
Magnolia, 83.
Marattia, 130.
Marattiaceæ, 125, 129.
— appearance of, 130.
— description of group, 129.
Marchantites, 163.
Medullosa, 72, 73, 119, 120, 121, 82, 83, 122, 123.
— foliage of, 121, 83.
— probable seeds of, 121.
— steles of, 72, 50, 73, 51, 120.
Mesozoic, character of flora, 40.
Metaxylem, 57, 31.
Mycorhiza, 165.
Micrococcus, 167.
Monocotyledons, 41, 44, 79.
— relative antiquity of, 81, 82.
Monostelic anatomy, 63, 126.
Mosses, scarcity of fossils of, 162.
Mosses, fossils of, 163.
Mountain building, from deposits under water, 6.
— — slow and continuous changes, 35.
Muscites, 163.
Mutation, 181.
Nematophycus, 166.
Neuropteris, leaf impression, 6, 13.
— foliage of Medullosa, 122.
— with seed attached, 122, 85.
Nipa, 85.
Nodules, 15, 16, 9.
Nucleus, 47, 17.
Oliver, 187.
Osmunda, 125.
Ovule, word unsuitable for palaeozoic “seeds”, 77.
Palisade cells, 55, 25.
— tissue in leaves, 58.
— — — fossil leaf, 59, 34.
Palms, 85.
Parenchyma, 55, 24.
Petrifaction of cells, 4.
Petrifactions, 17.
— of forest débris, 18.
— treatment of specimens of, 184.
Phyllotheca, 173.
Plant, parts of, the same in living and fossil, 59.
— world, main families in, 44.
Platanus, 83.
Polypodiaceæ, 124.
Polystelic anatomy, 63, 72.
Populus, 83, 85.
Poroxyleæ, 88.
— description of group of, 96.
Poroxylon, anatomy of, 97, 116.
Primitive plants, 46.
Primofilices, 132.
Protococcoideæ, 47, 17.
Protodammara, 89.
Protoplasm, 47.
Protostele, 62, 70.
Protoxylem, 57, 31.
Psaronius, 129, 130.
— stem anatomy of, 131, 91.
Pteridophytes, development of secondary wood in fossil forms of, 72.
Pteridosperms, 44, 104, 114, 131.
— description of group, 114 et seq.
— general distribution of in time, 177.
— summary of characters of, 123.
Pteris aurita, 62.
Quarries, 7, 1.
Quercus, 83, 85.
Race senility, 180.
Ranales, 103.
Renault, 2, 156, 187.
Reproductive organs, likeness between those of living and fossil plants, 67, 45, 46.
— — peculiar characters of some from the Palæozoic, 74.
— — simplicity of essential cells of, 52.
Rocks, persistence of mineral constituents, 36.
— fossils varying in according to the geological age, 37 et seq.
Roof of coal seam, 24, 13, 25, 14.
Roots, likeness of structure in living and fossil, 60, 35.
Salix, 83.
Sambucus, 84.
Schizoneura, 173.
Sclerenchyma, 56, 26, 59, 34.
Scott, 2, 160, 187.
Secondary wood, development of in fossil members of families now lacking it, 72.
Seeds, series of types from spores to seeds, 75, 76, 52-58.
— position on the plant, 77, 78.
— Tertiary impressions of, 80, 81, 60.
Selaginella, 75, 133, 134.
— with four spores in a sporangium, 75, 53.
Sequoia, 86.
Seward, 187.
“Shade leaves”, 171.
Shale, 7, 1, 11, 24, 25, 36.
Sieve tubes, 57, 32.
Sigillaria, 142, 145.
Sigillaria, cast of leaf bases, 9, 2, 144, 102.
— description of, 144.
Silica, 17.
Silicified wood, 17, 80, 87.
Solms Laubach, 2, 187.
Specimens, treatment of, 184.
Sphenophyllales, 44, 153.
— description of, 153.
— general distribution in time, 177.
Sphenophyllum, 44, 153, 154, 160.
— cone of, 157, 116.
— fertile, 158.
— impression of foliage, 154, 112.
— plurifoliatum, 153.
— sporangia of, 158, 117.
— stem anatomy, 155, 113, 156, 114.
— stem in coal ball, 20.
— wood of, 156, 114, 115.
Sphenopteris, leaf impression, 11, 5.
— foliage of Pteridosperms, 115, 77.
Sporangium of ferns, 67, 45.
— of lycopods, 67, 46.
— of pteridophytes, 75, 52, 53, 54.
Spores, germinating, in fossil sporangia, 68, 47.
— peculiar structures among palæozoic examples of, 74.
— series of types from “spores” to “seeds”, 75, 76, 52-58.
— tetrads of, 75, 52, 53, 54.
Sporophyll, 75, 52, 53, 54.
Stangeria, 110.
Stele, modifications of, 62, 36-42.
Stems, external similarity in living and fossil, 60.
Sternbergia, cast of, 10, 4.
— pith cast of Cordaites, 93.
Stigmaria, 69, 142, 143, 144, 145.
— rootlet of, 143, 101.
Stomates, 54, 23.
— in fossil epidermis, 14, 8.
Stoneworts, 163.
Synclines, 23.
Taxeæ, 88, 90.
— comparison of fructification with that of Cordaiteæ, 95.
— description of, 92.
Taxeæ, fleshy seeds of, 89.
Taxodium, 86.
Taxus, 82.
Time, divisions of geological time, 34.
Tracheides for water storage, 56, 30.
Tree-ferns, 130.
Trigonocarpus, 11, 76, 82, 122, 84.
— once supposed to be a Monocotyledon, 82.
— probably the seed of Medullosa, 121.
Tubicaulis, 127, 89.
Unexplored world, 3.
Unicellular plants, 47, 17.
— — division of cells in, 47, 48, 18.
“Vascular bundles”, relation of to steles, 65, 42.
— tissue, 57, 31, 32, 33, 59.
— — continued growth of, 65, 43.
— — importance in plant anatomy, 61 et seq.
Viburnum, 84, 85.
Watts, 187.
Westphalia, 19.
Wieland, 2, 102, 187.
Williamson, 2, 187.
Williamsonia, 104.
Wood, cells composing, 57, 31.
— centrifugal development of, 97, 65.
— centripetal development of, 97, 65.
— parenchyma, 57, 31.
— silicified, 17, 80, 87.
— solid rings of formed by cambium, 66, 44.
— vessels of Angiosperms, 58.
Yellowstone Park, 17, 167.
Yew, 82.
Yucca, 82.
Zeiller, 2, 187.
Zittel, 187.
Zygopteris, 127.