ClipArt ETC
"Diagram to show the activities going on in a palisade cell. The arrows from the chloroplasts into the cell cavity indicate movement of photosynthesized product. The thickness of the arrow shafts under "Light" indicate the relative light intensities." -Stevens, 1916

Palisade Cell

"Diagram to show the activities going on in a palisade cell. The arrows from the chloroplasts into the…

"B, cell of Spirogyra, with spiral chloroplast at c, nucleus at n, and pyrenoid at e." -Stevens, 1916

Spirogyra Chloroplast

"B, cell of Spirogyra, with spiral chloroplast at c, nucleus at n, and pyrenoid at e." -Stevens, 1916

"C, cross section of Spirogyra cell, with nucleus at n, and section of chloroplast and pyrenoid below." -Stevens, 1916

Spirogyra Chloroplast

"C, cross section of Spirogyra cell, with nucleus at n, and section of chloroplast and pyrenoid below."…

"D, cell of Oedogonium, with numerous chloroplasts." -Stevens, 1916

Oedogonium Chloroplast

"D, cell of Oedogonium, with numerous chloroplasts." -Stevens, 1916

"Showing pitted connections between medullary rays and xylem parenchyma, and between contiguous xylem parenchyma cells. m, medullary rays; n, xylem parenchyma. Camera-lucida drawing of tangential section of wood of yellow poplar." -Stevens, 1916

Yellow Poplar Wood

"Showing pitted connections between medullary rays and xylem parenchyma, and between contiguous xylem…

"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 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…

"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,…

"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;…

"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…

"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…

"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, 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 wood duck.

Wood Duck

The wood duck.

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…

Illustration of a child hauling wood at 5:00. It can be used to write mathematics story problems involving telling time and roman numerals.

Telling Time 5:00 Story Problem

Illustration of a child hauling wood at 5:00. It can be used to write mathematics story problems involving…

"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.…

"Stages in the division of a grandmother cell of microspores or pollen grains of a lily, somewhat diagrammatic. 14, split chromosomes of 13 aligned at the equator ready for the longitudinal halves of each to be drawn apart to opposite poles." -Stevens, 1916

Division of Grandmother Cell Stage 14

"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. 15, separation of the longitudinal halves." -Stevens, 1916

Division of Grandmother Cell Stage 15

"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. 16, formation of granddaughter nuclei, or nuclei of the spores." -Stevens, 1916

Division of Grandmother Cell Stage 16

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

"Stages in the formation of the megaspore, its germination, fertilization of the egg and endosperm cells. D, more highly magnified drawing of o in A showing archesporial cell at a." -Stevens, 1916

Megaspore Formation Stage 4

"Stages in the formation of the megaspore, its germination, fertilization of the egg and endosperm cells.…

"Stages in the formation of the megaspore, its germination, fertilization of the egg and endosperm cells. E, a, archesporial cell enlarged and ready for division; nu, tissue of the nucellus." -Stevens, 1916

Megaspore Formation Stage 5

"Stages in the formation of the megaspore, its germination, fertilization of the egg and endosperm cells.…

"Stages in the formation of the megaspore, its germination, fertilization of the egg and endosperm cells. F, a, archesporial cell dividing, nu, nucellus." -Stevens, 1916

Megaspore Formation Stage 6

"Stages in the formation of the megaspore, its germination, fertilization of the egg and endosperm cells.…

"Stages in the formation of the megaspore, its germination, fertilization of the egg and endosperm cells. G, row of four megaspores descended from the archesporial cell, only the upper one, m, functional, the other soon disintegrate." -Stevens, 1916

Megaspore Formation Stage 7

"Stages in the formation of the megaspore, its germination, fertilization of the egg and endosperm cells.…

"Stages in the formation of the megaspore, its germination, fertilization of the egg and endosperm cells. J, continued nuclear division has resulted in eight, namely, three antipodal nuclei, an, at the upper end of the megaspore cavity, two polar nuclei, l, in process of fusion, egg cell, eg, two synergids, s, s." -Stevens, 1916

Megaspore Formation Stage 10

"Stages in the formation of the megaspore, its germination, fertilization of the egg and endosperm cells.…

"Stages in the formation of the megaspore, its germination, fertilization of the egg and endosperm cells. K, showing only the lower half of the megaspore or embryo-sac cavity, with pollen tube, pt, and male nucleus, mn, fusing with egg cell, eg, and second male nucleus, mn2, uniting with primary endosperm nucleus, pe; s, synergid." -Stevens, 1916

Megaspore Formation Stage 11

"Stages in the formation of the megaspore, its germination, fertilization of the egg and endosperm cells.…

"Stages in the formation of the megaspore, its germination, fertilization of the egg and endosperm cells. L, later stage in the embryo-sac, an, antipodal cells, em, beginning of the embryo by division of fertilized egg cell; five dividing nuclei descended from primary endosperm nucleus." -Stevens, 1916

Megaspore Formation Stage 12

"Stages in the formation of the megaspore, its germination, fertilization of the egg and endosperm cells.…

Of the lily family (Liliaceae), the wood lily, or Lilium Philadelphicum.

Wood Lily

Of the lily family (Liliaceae), the wood lily, or Lilium Philadelphicum.

Of the orchid family (Orchidaceae), the green wood orchis or Habenaria clavellata.

Green Wood Orchis

Of the orchid family (Orchidaceae), the green wood orchis or Habenaria clavellata.

Of the crowfoot family (Ranunculaceae): top, wood anemone (Anemone quinquefolia); middle, rue anemone (Anemonella thalictrroides); bottom, liverwort (Hepatica triloba).

Wood Anemone, Rue Anemone, and Liverwort

Of the crowfoot family (Ranunculaceae): top, wood anemone (Anemone quinquefolia); middle, rue anemone…

Of the sorrel family (Oxalidaceae), the wood sorrel or Oxalis Acetosella.

Wood Sorrel

Of the sorrel family (Oxalidaceae), the wood sorrel or Oxalis Acetosella.

Of the sorrel family (Oxalidaceae), the yellow wood or lady's sorrel (Oxalis stricta), hairy in all parts.

Yellow Wood Sorrel

Of the sorrel family (Oxalidaceae), the yellow wood or lady's sorrel (Oxalis stricta), hairy in all…

Of the sorrel family (Oxalidaceae), the yellow wood or lady's sorrel (Oxalis corniculata), generally smooth.

Yellow Wood Sorrel

Of the sorrel family (Oxalidaceae), the yellow wood or lady's sorrel (Oxalis corniculata), generally…

"Diagram of cell structure. Pl. Plastids in cytoplasm. cc. Centrosome. n. Nucleolus. Chr. Chromosomes. N. Nucleus. ct. General cytoplasm. V. Vacuole. Gr. Granules." -Thomson, 1916

Cell Structure

"Diagram of cell structure. Pl. Plastids in cytoplasm. cc. Centrosome. n. Nucleolus. Chr. Chromosomes.…

"Diagram of cell division. chr., Chromosomes forming an equatorial plate; cs., centrosome." -Thomson, 1916

Cell Division

"Diagram of cell division. chr., Chromosomes forming an equatorial plate; cs., centrosome." -Thomson,…

"Life history of a coral, Monoxenia darwinii. A, B, Ovum. C, Division into two. D, four-cell stage. E, Blastula. F, Free-swimming blastula with cilia. G, Section of blastula. H, Beginning of invagination. I, Section of completed gastrula, showing ectoderm, and archenteron. K, Free-swimming ciliiated gastrula." -Thomson, 1916

Coral Stages

"Life history of a coral, Monoxenia darwinii. A, B, Ovum. C, Division into two. D, four-cell stage.…

"Paramoecium. ad. Adult form, showing cilia, "mouth," contractile vacuoles, etc. div. Transverse division. con. Conjugation." -Thomson, 1916

Paramecium

"Paramoecium. ad. Adult form, showing cilia, "mouth," contractile vacuoles, etc. div. Transverse division.…

"Life history of Monocystis. 1. Young Gregarine lying within a sperm mother cell of earthworm. 2. Association of two Gregarines within a cyst, ready to form gametes. 3. Numerous spore-cases (sp.c., pseudonavicellae) within a cyst. 4. A spore-case with eight spores (sp.) and a residual core (rb)." -Thomson, 1916

Monocystis

"Life history of Monocystis. 1. Young Gregarine lying within a sperm mother cell of earthworm. 2. Association…

"Life history of Gregarina. 1. Young forms (a, b, c) emerging from intestinal cells (i.c.); i.n., nucleus of intestinal cell. 2. Two forms conjugating (G. blattarum). 3. Spore formation within a cyst. 4. Adult with deciduous head-cap (c.c.), and a cuticular partition dividing the cell into an anterior part (A) and a posterior part (B); n., the nucleus. 5. A spore within its spore-case (sp.c.)." -Thomson, 1916

Gregarina

"Life history of Gregarina. 1. Young forms (a, b, c) emerging from intestinal cells (i.c.); i.n., nucleus…

"Life history of Coccidium. 1. Sporozoite; 2. Sporozoite entering a cell and becoming a trophozoite; 3-4. Schizont, forming merozoites; 5. Merozoites entering another cell; 6a. Merozoite forming macrogamete; 6b. Merozoite forming microgametes; 7. Free microgamete; 8-9. Fertilisation of macrogamete by microgamete; 10. Zygote within oocyst; 11. Formation of spores within oocyst; 12. Spores forming sporozoites." -Thomson, 1916

Coccidium

"Life history of Coccidium. 1. Sporozoite; 2. Sporozoite entering a cell and becoming a trophozoite;…

"Development of Polygordius. a., Mother sperm cell; b., c., sperm morulae; d., spermatosoa. 1. Ovum with large nucleus; 2. two-cell stage; 3. four-cell stage; 4. blastosphere; 5. gastrula; ac., archenteron; 6. closure of gastrula mouth or blastopore; 7. formation of stomodaeum (st.), and proctodaeum (pr.), which invaginate to meet archenteron (ac.); 8. complete gut formed; 9. elongation of larva; ap. sp., posterior segments; 11. form of adult Polygordius." -Thomson, 1916

Polygordius

"Development of Polygordius. a., Mother sperm cell; b., c., sperm morulae; d., spermatosoa. 1. Ovum…

A queen bee and queen cell in which it develops, opened and closed.

Queen Bee

A queen bee and queen cell in which it develops, opened and closed.

"Early stages in the development of Amphioxus. 1. Ovum with germinal vesicle; 2. four-cell stage; 3. external appearance of blastula; 4. blastula in section; 5. beginning of gastrula stage; 6. section of completed gastrula." -Thomson, 1916

Lancelet Stages

"Early stages in the development of Amphioxus. 1. Ovum with germinal vesicle; 2. four-cell stage; 3.…

A particle of human blood as it appears when transparent and floating. 2. the same, seen as illuminated. 3. the same, one half illuminated. 4. a particle of frog's blood floating. 5. the same, seen edgewise. All these objects are magnified 500 diameters.

Blood Particle

A particle of human blood as it appears when transparent and floating. 2. the same, seen as illuminated.…

"Diagram showing the principal parts of the cell as it appeaers when killed and stained. The protoplasm shows more of a meshwork (cy), the spaces representing the alveoli. f, formed substance in alveoli." -Galloway, 1915

Cell Parts

"Diagram showing the principal parts of the cell as it appeaers when killed and stained. The protoplasm…

"Direct cell division (Amoeba). A, active specimen with pseudopodia; B, becoming spherical preliminary to division; C, beginning of elongation and constriction; D, later stage; E, daughter cells forming pseudopodia. ec, clear ectoplasm; en, granular endoplasm; f, food vacuole; n, nucleus; ps, pseudopodium; v, pulsating vacuole." -Galloway, 1915

Amoeba Cell Division

"Direct cell division (Amoeba). A, active specimen with pseudopodia; B, becoming spherical preliminary…