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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 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 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 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 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…

"Simple microtome for clamping to table. P, P, plate glass ways for the section knife; S, milled-head for clamping the object; M, micrometer milled-head for turning the screw that raises the object as the sections are cur; C, milled-head for clamping the microtome to the table." -Stevens, 1916

Microtome

"Simple microtome for clamping to table. P, P, plate glass ways for the section knife; S, milled-head…

"Showing the manner of holding the knife blade on the glass ways, and, by the arrow, the direction of sliding he knife while cutting the sections." -Stevens, 1916

Microtome and Razor

"Showing the manner of holding the knife blade on the glass ways, and, by the arrow, the direction of…

"A sliding microtome of simple construction, adapted to cutting all kinds of sections." -Stevens, 1916

Sliding Microtome

"A sliding microtome of simple construction, adapted to cutting all kinds of sections." -Stevens, 1916

"Turn table for cementing coverglasses to slides. For use where the mounting medium is glycerine or glycerine jelly." -Stevens, 1916

Mounting Plant Sections

"Turn table for cementing coverglasses to slides. For use where the mounting medium is glycerine or…

"Nucleus dividing by simple constriction. From the lining of the embryo-sac of Vicia faba." -Stevens, 1916

V. Faba Nucleus Division

"Nucleus dividing by simple constriction. From the lining of the embryo-sac of Vicia faba." -Stevens,…

"Cross-sections of leaves of an oak (Quercus novimexicana), showing the effect of different light conditions on the internal anatomy. 1, from leaf growing in sunlight; 2, from leaf growing in the shade." -Gager, 1916

Oak Leaf Cross-Section

"Cross-sections of leaves of an oak (Quercus novimexicana), showing the effect of different light conditions…

"A, embryonic cells from onion root tip; d, plasmatic membrane; c, cytoplasm; a, nuclear membrane enclosing the thread-like nuclear reticulum; b, nucleolus; e, plastids (black dots scattered about)." -Stevens, 1916

Onion Cells

"A, embryonic cells from onion root tip; d, plasmatic membrane; c, cytoplasm; a, nuclear membrane enclosing…

"B, older (onion) cells farther back from the root tip. The cytoplasm is becoming vacuolate; f, vacuole." -Stevens, 1916

Onion Cells

"B, older (onion) cells farther back from the root tip. The cytoplasm is becoming vacuolate; f, vacuole."…

"Diagrammatic representation of a single palisade cell, with chloroplasts lining the walls." -Stevens, 1916

Palisade Cell

"Diagrammatic representation of a single palisade cell, with chloroplasts lining the walls." -Stevens,…

"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…

"Diagram to show the intake of carbon dioxide by the palisade cells from the intercellular spaces, the absorption by the chloroplasts of water from the cell-sap, and the passage of food from the chloroplasts into the cell-sap." -Stevens, 1916

Palisade Cell Intake

"Diagram to show the intake of carbon dioxide by the palisade cells from the intercellular spaces, the…

"Starch grains from the palisade cells of a Euphorbia leaf." -Stevens, 1916

Euphorbia Palisade Cells

"Starch grains from the palisade cells of a Euphorbia leaf." -Stevens, 1916

"Diagram to show the effect of different portions of the spectrum on photosynthesis. a to F, different regions of the spectrum from red to blue. A filamentous alga lies across these, and bacteria are collecting about the alga, with greatest frequency in the red between B and C, indicating the greatest evolution of oxygen there." -Stevens, 1916

Photosynthesis

"Diagram to show the effect of different portions of the spectrum on photosynthesis. a to F, different…

"Diagrammatic representation of a block of pine wood highly magnified. a, Early growth; b, late growth; c, intercellular space; d, bordered pit in tangential wall of late growth; m, f and e, bordered pit in radial wall of early growth from different points of view; h, row of medullary cells for carrying food; g, row of medullary ray cells for carrying water; k, thin place in radial wall of ray cells that carry food." -Stevens, 1916

Magnified Pine

"Diagrammatic representation of a block of pine wood highly magnified. a, Early growth; b, late growth;…

"Different stages in the development of a bordered pit. b, The original, thin, primary wall; a, the overhanging border formed as the wall thickened. B, Thickening of the wall has continued and extended the border; the primary wall has thickened at c, forming the torus. C, the border and the torus are finished." -Stevens, 1916

Pit Development

"Different stages in the development of a bordered pit. b, The original, thin, primary wall; a, the…

First stage in plant cell division: Protophase 1; "Resting cell ready to begin division." -Stevens, 1916

Plant Cell Division 1

First stage in plant cell division: Protophase 1; "Resting cell ready to begin division." -Stevens,…

Second stage in plant cell division: Protophase 2; "the nuclear reticulum is assuming the form of a thickened thread, and the cytoplasm at opposite poles is becoming thread-like to form the spindle fibers." -Stevens, 1916

Plant Cell Division 2

Second stage in plant cell division: Protophase 2; "the nuclear reticulum is assuming the form of a…

Third stage in plant cell division: Protophase 3; "The nuclear thread has divided longitudinally throughout the middle, and the spindle fibers have become more definite." -Stevens, 1916

Plant Cell Division 3

Third stage in plant cell division: Protophase 3; "The nuclear thread has divided longitudinally throughout…

Fourth stage in plant cell division: Protophase 4; "The nuclear membrane and the nucleolus have disappeared, and the nuclear thread has become segmented into chromosomes which are assembling at the equator of the cell." -Stevens, 1916

Plant Cell Division 4

Fourth stage in plant cell division: Protophase 4; "The nuclear membrane and the nucleolus have disappeared,…

Fifth stage in plant cell division: Metaphase; "The metaphase, where the longitudinal halves of the chromosomes are being drawn apart preparatory to their journey toward opposite poles." -Stevens, 1916

Plant Cell Division 5

Fifth stage in plant cell division: Metaphase; "The metaphase, where the longitudinal halves of the…

Sixth stage in plant cell division: Anaphase; "The anaphase, or movement of the chromosomes toward the poles, is about completed, connecting fibers extend from pole to pole." -Stevens, 1916

Plant Cell Division 6

Sixth stage in plant cell division: Anaphase; "The anaphase, or movement of the chromosomes toward the…

Seventh stage in plant cell division: Telophase; "Telophase where the chromosomes have begun to spin out in the form of a nuclear reticulum. The connecting fibers have begun to thicken in the equatorial plane." -Stevens, 1916

Plant Cell Division 7

Seventh stage in plant cell division: Telophase; "Telophase where the chromosomes have begun to spin…

Eighth stage in plant cell division: "The connecting fibers have spread out and come into contact with the wall of the mother cell in the equatorial plane, and the thickening of the fibers throughout this plane has made a complete cell plate within which the dividing wall will be produced." -Stevens, 1916

Plant Cell Division 8

Eighth stage in plant cell division: "The connecting fibers have spread out and come into contact with…

Ninth and final stage in plant cell division: "A nuclear membrane has been formed about each daughter nucleus, and the dividing cell-wall is complete." -Stevens, 1916

Plant Cell Division 9

Ninth and final stage in plant cell division: "A nuclear membrane has been formed about each daughter…

"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,…

"Diagram to show the topography and character of the tissues that evolved from the primary meristems. Cambial activity has not yet begun." -Stevens, 1916

Plant Tissues

"Diagram to show the topography and character of the tissues that evolved from the primary meristems.…

"Diagram showing additions to the primary tissues through the activity of the cambium and phellogen or cork cambium." -Stevens, 1916

Plant Tissues

"Diagram showing additions to the primary tissues through the activity of the cambium and phellogen…

"Diagram showing the relation of this year's leaves to the wood of the current year." -Stevens, 1916

Plant Tissues

"Diagram showing the relation of this year's leaves to the wood of the current year." -Stevens, 1916

"Apex of root hair flattened out over and imbedding soil particles." -Stevens, 1916

Plant Root Hair

"Apex of root hair flattened out over and imbedding soil particles." -Stevens, 1916

"A single root hair on a large scale, showing that it is an outgrowth of an epidermal cell, and the fact that it possesses a living protoplast and large vacuole filled with cell-sap and traversed by cytoplasmic strands. The nucleus is near the apex of the hair." -Stevens, 1916

Plant Root Hair

"A single root hair on a large scale, showing that it is an outgrowth of an epidermal cell, and the…

"Cross section of a root in the region of the root hairs." -Stevens, 1916

Plant Root Hairs

"Cross section of a root in the region of the root hairs." -Stevens, 1916

"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,…

"Portion of a cross section of a root of Allium ascalonicum. h, large central, tracheal tube; i, xylem, and l, phloem portion of the vascular bundle; n, cortex cells; 1, endodermis with thin-walled cell at k to admit passage of materials; m, pericycle or pericambium." -Stevens, 1916

A. Ascalonicum Root

"Portion of a cross section of a root of Allium ascalonicum. h, large central, tracheal tube; i, xylem,…

<i>Lolium perenne</i>. A sheath, in botany is "the part of an expanded organ that is rolled around a stem or other body, forming a tube, as in the lower part of the leaves of grasses..." &mdash;Whitney, 1889 <p>This illustration show a single leaf of ryegrass in its sheath.

Ryegrass Leaf with Sheath

Lolium perenne. A sheath, in botany is "the part of an expanded organ that is rolled around a stem or…

"Diagram showing the progressive development of the skeletal tissues from the apex toward the base of the stem." -Stevens, 1916

Plant Skeletal Tissues

"Diagram showing the progressive development of the skeletal tissues from the apex toward the base of…

"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;…

"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,…

"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;…

"Diagram showing some types of unusual growth in thickness. A, cross section through a four-year-old stem of Anisostichus capreolata." -Stevens, 1916

A. Capreolata Unusual Stem Growth

"Diagram showing some types of unusual growth in thickness. A, cross section through a four-year-old…

"Diagram showing some types of unusual growth in thickness...B, cross section of stem of species of Bauhinia; the xylem strands, b, are stippled while the surrounding parenchyma and bark tissues are left white." -Stevens, 1916

Bauhinia Unusual Stem Growth

"Diagram showing some types of unusual growth in thickness...B, cross section of stem of species of…

"Diagram showing some types of unusual growth in thickness...C, portion of a cross section of stem of Gnetum scandens; 1, 2, and 3 are successive rings of growth; m, is the pith; b, is a sclerenchyma ring. The xylem portions with the exception of the larger tracheal tubes are shaded, while the medullary rays, phloem and tissues intervening between the rings of growth and the outer cortes tissues are left white." -Stevens, 1916

G. Scandens Unusual Stem Growth

"Diagram showing some types of unusual growth in thickness...C, portion of a cross section of stem of…

The cross section of the stem of hop, which carries large amounts of water.

Hop Stem Tissue

The cross section of the stem of hop, which carries large amounts of water.

The cross section of the stem of Pisdium Galapageium, which carries very little water.

P. Galapageium Stem Tissue

The cross section of the stem of Pisdium Galapageium, which carries very little water.

The cross section of the stem of water cress, which carries very little water.

Water Cress Stem Tissue

The cross section of the stem of water cress, which carries very little water.

The cross section of the stem of yellow poplar, which carries large amounts of water.

Yellow Poplar Stem Tissue

The cross section of the stem of yellow poplar, which carries large amounts of water.

"Adianium pedatum: transverse section of stem, showing the amphiphloic siphonostele." -Stevens, 1916

A. Pedaium Stem

"Adianium pedatum: transverse section of stem, showing the amphiphloic siphonostele." -Stevens, 1916

"Diagram showing the course of the vascular bundles in a stem of Clematis viticella. Median bundles from the leaves are marked A, lateral bundles B and C." -Stevens, 1916

C. Viticella Stem

"Diagram showing the course of the vascular bundles in a stem of Clematis viticella. Median bundles…

"B, diagram of vascular bundles in external view and in cross section of the stem of Cerastium. The leaves are shown cut off at 1, 2, 2' and 3." -Stevens, 1916

Cerastium Stem

"B, diagram of vascular bundles in external view and in cross section of the stem of Cerastium. The…

"Portion of a cross section throughout the stem of Dracaena marginata. P, parenchyma of cortex. V, meristematic zone of the pericycle by the activity of which the stem increases in diameter, with the addition of new vascular bundles. M, mature vascular bundle. N, nearly mature vascular bundle. O, newly formed procambium strand from which a vascular bundle is to arise. B, beginning of a procambium strand by the division of cells in the meristematic zone. F, parenchyma of the fundamental tissue." -Stevens, 1916

D. Marginata Stem

"Portion of a cross section throughout the stem of Dracaena marginata. P, parenchyma of cortex. V, meristematic…

"Gleichenia pubescens: transverse section of stem, showing the protostele." -Stevens, 1916

G. Pubescens Stem

"Gleichenia pubescens: transverse section of stem, showing the protostele." -Stevens, 1916

"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,…

"A, cross section of stem of Juncus...the black lines traversing the section are really chains of cells and thin-walled cells with relatively large intercellular spaces between them fill up i." -Stevens, 1916

Juncus Stem

"A, cross section of stem of Juncus...the black lines traversing the section are really chains of cells…

"B, stem of Nymphaea, showing large intercellular spaces at i." -Stevens, 1916

Nymphaea Stem

"B, stem of Nymphaea, showing large intercellular spaces at i." -Stevens, 1916

"Pteris aquilina: transverse section of stem, showing the polystele." -Stevens, 1916

P. Aquilina Stem

"Pteris aquilina: transverse section of stem, showing the polystele." -Stevens, 1916

"Cross section of a portion of palm stem. e, xylem; f, phloem portions of vascular bundle; g, sclerenchyma tissue about vascular bundle; d, fundamental or ground tissue; c, larger tracheal tubes in vascular bundle." -Stevens, 1916

Palm Stem

"Cross section of a portion of palm stem. e, xylem; f, phloem portions of vascular bundle; g, sclerenchyma…