ClipArt ETC
"Outline of tangential section of wood of oak, to show frequency of medullary rays. The section is 1 mm. square. The number of rays shown is below the average for woodyplants." -Stevens, 1916

Oak Wood

"Outline of tangential section of wood of oak, to show frequency of medullary rays. The section is 1…

"Diagram indicating the succession of the conducting tissues of a vein from the base toward the apex. a, border parenchyma; b, companion cells; c, sieve tubes; d, undivided mother cells of companion cells and sieve tubes; e, tracheal elements." -Stevens, 1916

Plant Vein

"Diagram indicating the succession of the conducting tissues of a vein from the base toward the apex.…

"Showing the effect of cutting across the veins on the removal of food from the leaf. A, all of the main veins are cut across near their bases; B, the mid-vein alone has been severed. The stippled areas indicated the starch reaction with the iodine test." -Stevens, 1916

Cut Leaf Veins

"Showing the effect of cutting across the veins on the removal of food from the leaf. A, all of the…

"Diagram illustrating the descent of food from the leaf into the stem, and its circulation upward and downward through the sieve tubes, and upward through the tracheal tissues." -Stevens, 1916

Leaf Food Circulation

"Diagram illustrating the descent of food from the leaf into the stem, and its circulation upward and…

"Diagram showing how, in Indian corn, the food from the upper and lower leaves finds its way into the ears." -Stevens, 1916

Indian Corn Food Circulation

"Diagram showing how, in Indian corn, the food from the upper and lower leaves finds its way into the…

"Diagram showing the transport of food through the sieve tubes, medullary rays and tracheal tubes, and its storage in the parenchyma cells of the wood and bark. The black bodies in the cells indicate stored food." -Stevens, 1916

Sieve Tube Food Transportation

"Diagram showing the transport of food through the sieve tubes, medullary rays and tracheal tubes, and…

"Diagram to show the relation of the food-conducting tissues of the leaf to those of the stem; and in the stem the relation of these tissues of one year to those of preceding years. The dotted line between phloem and xylem stands for the cambium. The figures at the bottom of the diagram indicate the age in years of the zones of tissues in phloem and xylem." -Stevens, 1916

Food Tissues

"Diagram to show the relation of the food-conducting tissues of the leaf to those of the stem; and in…

"Tangential section through the wood of grapevine. m, cells of medullary ray, and n, of xylem parenchyma, packed full of starch." -Stevens, 1916

Grapevine Wood

"Tangential section through the wood of grapevine. m, cells of medullary ray, and n, of xylem parenchyma,…

"Starch from different sources. A, curcuma starch; B, corn starch; C, tapioca starch; D, rice starch, showing compound grains." -Stevens, 1916

Starch

"Starch from different sources. A, curcuma starch; B, corn starch; C, tapioca starch; D, rice starch,…

"Sphaero-crystals of unilin from tuber of Dahlia variabilis. A, precipitated from an aqueous solution; B, precipitated within the cells by long standing in alcohol." -Stevens, 1916

Sphaero-Crystals

"Sphaero-crystals of unilin from tuber of Dahlia variabilis. A, precipitated from an aqueous solution;…

"Storage tissues of the cotyledon of Impatiens Balsamina. A, from the resting seed, and B, from a germinating seed. In B the amyloid thickenings of the cell-walls are partly digested away." -Stevens, 1916

I. Balsamina Storage Tissues

"Storage tissues of the cotyledon of Impatiens Balsamina. A, from the resting seed, and B, from a germinating…

"To show aleurone grains. A, cells from cotyledon of seed of garden bean; n, aleurone grains; m, starch; B, cells from endosperm of castor bean; a, aleurone grains; l, ground substance; k, crystalloid; j, globoid." -Stevens, 1916

Aleurone Grains

"To show aleurone grains. A, cells from cotyledon of seed of garden bean; n, aleurone grains; m, starch;…

"Showing concentric and eccentric striations of starch grains. e, potato starch eccentrically striated; f, compound starch grain from potato; g, bean starch concentrically striated." -Stevens, 1916

Starch Grain Striations

"Showing concentric and eccentric striations of starch grains. e, potato starch eccentrically striated;…

"Tangential section of wood of Liriodendron tulipifera, showing frequency of contact of medullary rays with a tracheal tube. f, medullary ray; g, tracheal tube." -Stevens, 1916

L. Tulipifera Wood

"Tangential section of wood of Liriodendron tulipifera, showing frequency of contact of medullary rays…

"Diagram to show food from the leaves descending through the sieve tubes and being stored in the medullary ray cells and xylem parenchyma." -Stevens, 1916

Plant Food Storage

"Diagram to show food from the leaves descending through the sieve tubes and being stored in the medullary…

"The digestion of the stored food and its ascent through the tracheal tubes when growth is resumed in the spring." -Stevens, 1916

Plant Food Digestion

"The digestion of the stored food and its ascent through the tracheal tubes when growth is resumed in…

"Enzyme-secreting cells of date cotyledon." -Stevens, 1916

Date Cotyledon

"Enzyme-secreting cells of date cotyledon." -Stevens, 1916

"Enzyme-secreting cells of...cotyledon of Indian corn." -Stevens, 1916

Indian Corn Cotyledon

"Enzyme-secreting cells of...cotyledon of Indian corn." -Stevens, 1916

"Longitudinal section through a digestive gland of Drosera rotundifolia." -Stevens, 1916

D. Rotundifolia Digestive Gland

"Longitudinal section through a digestive gland of Drosera rotundifolia." -Stevens, 1916

"Cross section of leaf of Mesembryanthemum Forskalii showing a large part of the leaf devoted to the storage of water. a, water-storage cells; b, chlorophyll-bearing cells; c, crystal of calcium oxalate." -Stevens, 1916

M. Forskalli Leaf

"Cross section of leaf of Mesembryanthemum Forskalii showing a large part of the leaf devoted to the…

"Water-storage tracheids in the leaf of Euphorbia splendens. b, b, water-storage tracheids; d, mesophyll cells; c, branch from a milk tube." -Stevens, 1916

E. Splendens Leaf

"Water-storage tracheids in the leaf of Euphorbia splendens. b, b, water-storage tracheids; d, mesophyll…

"Glandular hair from the petiole of Pelargonium zonale. e, secretion from the globular gland on which it rests." -Stevens, 1916

Hair, P. Zonale

"Glandular hair from the petiole of Pelargonium zonale. e, secretion from the globular gland on which…

"Portion of a cross section through a nectariferous bract of Vicia sepium; n, nectar-secreting cells." -Stevens, 1916

V. Sepium Bract

"Portion of a cross section through a nectariferous bract of Vicia sepium; n, nectar-secreting cells."…

"Formation of an interior, globular, lysigenous gland of the leaf of Dictamnus fraxinella. A, g, g and c, mother cells of the gland; c, from the protoderm, and g, g, from the fundamental tissue. B, older stage where the cells have begun to form the secretion." -Stevens, 1916

D. Fraxinella Gland Formation

"Formation of an interior, globular, lysigenous gland of the leaf of Dictamnus fraxinella. A, g, g and…

"Cross section through a portion of orange peel showing the cavity of an interior, globular gland at g; crystals of hesperidin at h; calcium oxalate crystals at k." -Stevens, 1916

Orange Peel Glands

"Cross section through a portion of orange peel showing the cavity of an interior, globular gland at…

"Schizogenous resin duct in the young stem of ivy (Hedera helix), as seen in cross section. A, early, and B, later stage in the formation of the duct. g, the mature duct; c, cambium wb, phloem; b, bast fibers." -Stevens, 1916

Ivy Stem

"Schizogenous resin duct in the young stem of ivy (Hedera helix), as seen in cross section. A, early,…

"Lysigenous gland in the leaf of Dictamnus fraxinella. B, young gland, with cells beginning to secrete oil; C, mature gland where the secreting cells have broken down and left their secretion within the cavity thus formed; o, large drop of secreted oil." -Stevens, 1916

Leaf Gland

"Lysigenous gland in the leaf of Dictamnus fraxinella. B, young gland, with cells beginning to secrete…

"Resin duct in leaf of Pinus silvestris, in cross section at A, and in longitudinal section at B; h, cavity surrounded by the secreting cells; f, f, sclerenchyma fibers surrounding and protecting the duct." -Stevens, 1916

Leaf Resin Duct

"Resin duct in leaf of Pinus silvestris, in cross section at A, and in longitudinal section at B; h,…

"Laticiferous vessels from the cortex of root of Scorozonora hispanica...B, smaller portion." -Stevens, 1916

Root Vessels

"Laticiferous vessels from the cortex of root of Scorozonora hispanica...B, smaller portion." -Stevens,…

"Glands from Pinguicula. A, upper surface of leaf showing long-stalked gland at m, and short-stalked gland at n. B, cross section through a short-stalked gland." -Stevens, 1916

Leaf Glands

"Glands from Pinguicula. A, upper surface of leaf showing long-stalked gland at m, and short-stalked…

"Different forms of crystals of calcium oxalate. A, from the petiole of Begonia manicata." -Stevens, 1916

Calcium Oxalate Crystals

"Different forms of crystals of calcium oxalate. A, from the petiole of Begonia manicata." -Stevens,…

"Cystoliths from the leaf of Ficus carica. A, complete cystolith; B, cystolith from which the calcium carbonate has been removed for use in other parts of the plant. B is from a leaf that had fallen off in autumn." -Stevens, 1916

Cystoliths

"Cystoliths from the leaf of Ficus carica. A, complete cystolith; B, cystolith from which the calcium…

"Glands from the leaf of Ribes nigrum. A, young stage in the development of the gland where the cuticle is already being pushed up by the secretion, i. B, complete gland; k, secreting cells; h, cavity between the secreting cells and cuticle occupied by the secretion." -Stevens, 1916

Leaf Glands

"Glands from the leaf of Ribes nigrum. A, young stage in the development of the gland where the cuticle…

"One-celled hydatode of Gonocaryum pyriforme, seen in cross section at A, and from the surface in B." -Stevens, 1916

G. Pyriforme Hydatode

"One-celled hydatode of Gonocaryum pyriforme, seen in cross section at A, and from the surface in B."…

"Hydatode from the leaf of Phaseolus multiflorus." -Stevens, 1916

P. Multiflorus Hydatode

"Hydatode from the leaf of Phaseolus multiflorus." -Stevens, 1916

"Radial longitudinal section through a hydatode from the leaf margin of Primula sinensis. i, upper, and j, lower epidermis; h, palisade cell; e, thin-walled parenchyma, called epithem; g, intercellular space; f, guard cell of a water stoma; k, tracheal elements." -Stevens, 1916

P. Sinensus Hydatode

"Radial longitudinal section through a hydatode from the leaf margin of Primula sinensis. i, upper,…

"A, B, C, D, Successive stages of growth of prothallium from the spore in Osmunda cinnamomea; E, growth of fern plant from fertilized egg within the prothallium of Osmunda Claytoniana." -Stevens, 1916

Fern Growth

"A, B, C, D, Successive stages of growth of prothallium from the spore in Osmunda cinnamomea; E, growth…

"A, Antheridium containing sperm cells; B, archegonium containing an egg cell which has been found by five sperm cells. All from Osmunda cinnamomea." -Stevens, 1916

Fern Reproduction

"A, Antheridium containing sperm cells; B, archegonium containing an egg cell which has been found by…

"Showing method of association of paternal and maternal chromosomes, at A in all vegetative nuclei, and B, C, D, their manner of separation in all vegetative nuclear divisions. Showing also manner of association of paternal and maternal chromosomes at E in early prophase of spore grandmother cells and the manner of their separation during the division of the grandmother-cell nucleus at F and G. Showing also the longitudinal division of the chromosomes in the spore mother cells in H, and their separation to form the spore nuclei in I, two of the four spores being purely paternal and two purely maternal." -Stevens, 1916

Plant Reproduction

"Showing method of association of paternal and maternal chromosomes, at A in all vegetative nuclei,…

The archesporium in the stages of "formation of anthers and pollen grains or microspores of Silphium." -Stevens, 1916

Microspore Archesporium

The archesporium in the stages of "formation of anthers and pollen grains or microspores of Silphium."…

The primary sporogenous cell (ps) and the primary parietal layer (ppr) in the stages of "formation of anthers and pollen grains or microspores of Silphium." -Stevens, 1916

Microspore Cells

The primary sporogenous cell (ps) and the primary parietal layer (ppr) in the stages of "formation of…

The inner layer (i), outer layer (o), sporogenous cells (s) in the stages of "formation of anthers and pollen grains or microspores of Silphium." -Stevens, 1916

Microspore Layers

The inner layer (i), outer layer (o), sporogenous cells (s) in the stages of "formation of anthers and…

The sporogenous cells (s), tapetum (t), two parietal layers (oo) in the stages of "formation of anthers and pollen grains or microspores of Silphium." -Stevens, 1916

Microspore Cells

The sporogenous cells (s), tapetum (t), two parietal layers (oo) in the stages of "formation of anthers…

The cross section of a mature anther lobe in the stages of "formation of anthers and pollen grains or microspores of Silphium." -Stevens, 1916

Microspore Anther Lobe

The cross section of a mature anther lobe in the stages of "formation of anthers and pollen grains or…

The anther and archesporium in the stages of "formation of anthers and pollen grains or microspores of Silphium." -Stevens, 1916

Microspore Anther

The anther and archesporium in the stages of "formation of anthers and pollen grains or microspores…

The pollen grains beginning to germinate in the stages of "formation of anthers and pollen grains or microspores of Silphium." -Stevens, 1916

Microspore Pollen Grains

The pollen grains beginning to germinate in the stages of "formation of anthers and pollen grains or…

The sporogenous cells (s), tapetum (t), two parietal layers (oo) in the stages of "formation of anthers and pollen grains or microspores of Silphium." -Stevens, 1916

Microspore Cells

The sporogenous cells (s), tapetum (t), two parietal layers (oo) in the stages of "formation of anthers…

The cross section of a mature anther lobe in the stages of "formation of anthers and pollen grains or microspores of Silphium." -Stevens, 1916

Microspore Anther Lobe

The cross section of a mature anther lobe in the stages of "formation of anthers and pollen grains or…

"Stages in the division of a grandmother cell of microspores or pollen grains of a lily, somewhat diagrammatic. 1, resting stage of a grandmother cell." -Stevens, 1916

Division of Grandmother Cell Stage 1

"Stages in the division of a grandmother cell of microspores or pollen grains of a lily, somewhat diagrammatic.…

"Stages in the division of a grandmother cell of microspores or pollen grains of a lily, somewhat diagrammatic. 2, nuclear thread becoming arranged into parallel threads." -Stevens, 1916

Division of Grandmother Cell Stage 2

"Stages in the division of a grandmother cell of microspores or pollen grains of a lily, somewhat diagrammatic.…

"Stages in the division of a grandmother cell of microspores or pollen grains of a lily, somewhat diagrammatic. 3, synaptic stage." -Stevens, 1916

Division of Grandmother Cell Stage 3

"Stages in the division of a grandmother cell of microspores or pollen grains of a lily, somewhat diagrammatic.…

"Stages in the division of a grandmother cell of microspores or pollen grains of a lily, somewhat diagrammatic. 4, parallel threads uniting." -Stevens, 1916

Division of Grandmother Cell Stage 4

"Stages in the division of a grandmother cell of microspores or pollen grains of a lily, somewhat diagrammatic.…

"Stages in the division of a grandmother cell of microspores or pollen grains of a lily, somewhat diagrammatic. 5, double threads so united as to appear as one." -Stevens, 1916

Division of Grandmother Cell Stage 5

"Stages in the division of a grandmother cell of microspores or pollen grains of a lily, somewhat diagrammatic.…

"Stages in the division of a grandmother cell of microspores or pollen grains of a lily, somewhat diagrammatic. 7, thread transversely segmented into double chromosomes." -Stevens, 1916

Division of Grandmother Cell Stage 7

"Stages in the division of a grandmother cell of microspores or pollen grains of a lily, somewhat diagrammatic.…

"Stages in the division of a grandmother cell of microspores or pollen grains of a lily, somewhat diagrammatic. 8, diakinesis, that is, chromosomes dispersed about the nuclear membrane." -Stevens, 1916

Division of Grandmother Cell Stage 8

"Stages in the division of a grandmother cell of microspores or pollen grains of a lily, somewhat diagrammatic.…

"Stages in the division of a grandmother cell of microspores or pollen grains of a lily, somewhat diagrammatic. 9, multipolar spindle stage." -Stevens, 1916

Division of Grandmother Cell Stage 9

"Stages in the division of a grandmother cell of microspores or pollen grains of a lily, somewhat diagrammatic.…

"Stages in the division of a grandmother cell of microspores or pollen grains of a lily, somewhat diagrammatic. 10, bipolar spindle with double chromosomes aligned at the equator." -Stevens, 1916

Division of Grandmother Cell Stage 10

"Stages in the division of a grandmother cell of microspores or pollen grains of a lily, somewhat diagrammatic.…

"Stages in the division of a grandmother cell of microspores or pollen grains of a lily, somewhat diagrammatic. 11, reduction division, the double chromosomes separating and at the same time showing longitudinal division, with the longitudinal halves widely apart at their equatorial ends." -Stevens, 1916

Division of Grandmother Cell Stage 11

"Stages in the division of a grandmother cell of microspores or pollen grains of a lily, somewhat diagrammatic.…

"Stages in the division of a grandmother cell of microspores or pollen grains of a lily, somewhat diagrammatic. 12, formation of daughter nuclei, which are really the nuclei of the mother cells of the spores." -Stevens, 1916

Division of Grandmother Cell Stage 12

"Stages in the division of a grandmother cell of microspores or pollen grains of a lily, somewhat diagrammatic.…

"Stages in the division of a grandmother cell of microspores or pollen grains of a lily, somewhat diagrammatic. 13, division of mother-cell nuclei, the longitudinally split chromosomes seen in 11 again appearing." -Stevens, 1916

Division of Grandmother Cell Stage 13

"Stages in the division of a grandmother cell of microspores or pollen grains of a lily, somewhat diagrammatic.…