[1] For apparatus, reagents, collection and preservation of material, etc., see Appendix.

[2] If spirogyra is forming fruit some of the threads will be lying parallel in pairs, and connected with short tubes. In some of the cells there will be found rounded or oval bodies known as zygospores. These may be seen in fig. 86, and will be described in another part of the book.

[3] The most suitable preparations of mucor for study are made by growing the plant in a nutrient substance which largely consists of gelatine, or, better, agar-agar, a gelatinous preparation of certain seaweeds. This, after the plant is sown in it, should be poured into sterilised shallow glass plates, called Petrie dishes.

[4] We should note that the coloring matter of the beet resides in the cell-sap. It is in these colored cells that we can best see the movement take place, since the red color serves to differentiate well the moving mass from the cell wall. The protoplasmic membrane at several points usually clings tenaciously so that at several places the membrane is arched strongly away from the cell wall as shown in fig. 24. While water is removed from the cell-sap, we note that the coloring matter does not escape through the protoplasmic membrane.

[5] See Chapter 38 for organization of members of the plant body.

[6] Demonstrations may be made with prepared sections of leaves,

[7] This ring and the bundles separate the stem into two regions, an outer one composed of large cells with thin walls, known as the cortical cells, or collectively the cortex. The inner portion, corresponding to what is called the pith, is made up of the same kind of cells and is called the medulla, or pith. When the cells of the cortex, as well as of the pith, remain thin walled the tissue is called parenchyma. Parenchyma belongs to the group of tissues called fundamental.

[8] In the formation of starch during photosynthesis the separated molecules from the carbon dioxide and water unite in such a way that carbon, hydrogen, and oxygen are united into a molecule of starch. This result is usually represented by the following equation: CO₂ + H₂O = CH₂O + O₂. Then by polymerization 6(CH₂O) = C₆H₁₂O₆ = grape sugar. Then C₆H₁₂O₆-H₂O = C₆H₁₀O₅ = starch. It is believed, however, that the process is much more complicated than this, that several different compounds are formed before starch finally appears, and that the formula for starch is much higher numerically than is represented by C₆H₁₀O₅.

[9] Paragraphs 156-160 were prepared by Dr. E. J. Durand.

[10] Make up three stock solutions as follows:

For Fehling’s solution take one volume of each of (1), (2), and (3), and to the mixture add two volumes of water.

[11] This solution of taka diastase should be made up cold. If it is heated to 60° C. or over it is destroyed.

[12] Calcium is not essential for the growth of the fungi.

[13] For example, silicon is used by some plants in strengthening supporting tissues. Buckwheat thrives better when supplied with a chloride.

[14] Evidence points to the belief that certain cells of the host form substances which attract, chemitropically, the fungus threads, and that in these cells the fungus threads are more abundant than in others. Furthermore in the vicinity of the nucleus of the host seems to be the place where these activities are more marked.

[15] In lieu of Arisæma make a practical study of the pea. See paragraph 216a.

[16] Dissolve a half gram of osmic acid in 50 cc. of water and keep tightly corked when not using.

[17] In Engler & Prantl’s Pflanzenfamilien, Wille uses the term class for these principal subdivisions of the algæ. Systematists are not yet agreed upon a uniform use of the terms.

[18] See Bot. Gaz., 17, 389, 1892.

[19] Class Myxomycetes, or Mycetozoa.—To this class belong the “slime molds,” low organisms consisting of masses of naked protoplasm which flows among decaying leaves and in decaying wood, coming to the surface to fruit. The fruit in many cases resembles miniature puff-balls, and these plants were formerly classed with the puff-balls. The spores germinate by forming swarm spores which unite to form a small plasmodium, which in turn grows to form a large plasmodium or protoplasmic mass. It is doubtful if they are any more plant than animal organisms. Examples: Trichia, Arcyria, Stemonitis, Physarum, Ceratiomyxa, etc., on rotten wood; Plasmodiophora brassicæ is a parasite causing club foot of cabbage, radishes, etc. It lives within the roots, causing large knots and swellings on the same.

[20] As suborder in Engler and Prantl.

[21] As suborder in Engler and Prantl.

[22] As suborder in Engler and Prantl.

[23] The Uredinales and Auriculariales in Engler and Prantl are placed in order, Auriculariineæ.

[24] The Uredinales and Auriculariales in Engler and Prantl are placed in order, Auriculariineæ.

[25] May be used as an alternate study for marchantia.

[26] As subclass in Engler and Prantl.

[27] As subclass in Engler and Prantl.

[28] As subclass in Engler and Prantl.

[29] Called the calyptra.

[30] As subclass in Engler and Prantl.

[31] As subclass in Engler and Prantl.

[32] As subclass in Engler and Prantl.

[33] As subclass in Engler and Prantl.

[34] As class Filicales in Engler and Prantl.

[35] As class Equisetales in Engler and Prantl.

[36] As class Lycopodiales in Engler and Prantl.

[37] Suggestions to the teacher.—In the study of the flowering plants in the secondary school and in elementary courses three general topics are suggested. 1st, the study of the form and members of the plant and their arrangement, as in Chapters XXXVIII-XLV. 2d, the study of a few plants representative of the more important families, in order that the members of the plant, as studied under the first topic, may be seen in correlation with the plant as a whole in a number of different types. 3d, the study of plants in their relation to environment, as in Chapter XLVI. The first and second topics can be conducted consecutively in the classroom and laboratory. The third topic can be studied at opportune times during the progress of topics 1 and 2. For example, while studying topic 1 excursions can be made to study winter conditions of buds, shoots, etc., if in winter period, or the relations of leaves, etc., to environment, if in the growing period. While studying topic 2 excursions can be made to study flower relations, and also vegetation relations to environment (see Chapters XLVI-LVII of the author’s “College Text-book of Botany”). It is believed that a study of these three general topics is of much more value to the beginning student than the ordinary plant analysis and determination of species.

[38] It is interesting to note that in some foliage shoots the stem is entirely subterranean. See discussion of the bracken fern and sensitive fern in Chapter XXXIX.

[39] Some fibers occur also very frequently in the Fundamental System, forming bundle-sheaths, or strands of mechanical tissue in the cortex.

[40] Besides these specialized shoots for the storage of food, food substances are stored in ordinary shoots. For example, in the trunks of many trees starch is stored. With the approach of cold weather the starch is converted into oil, in the spring it is converted into starch again, and later as the buds begin to grow the starch is converted into glucose to be used for food. In many other trees, on the other hand, the starch changes to sugar on the approach of winter.

[41] This topic was prepared by Dr. K. M. Wiegand.

[42] See discussion of Tropophytes in Chapter XLVI.

[43] Chapter V, and Organization of Tissues in Chapter XXXVIII.

[44] Some of the different terms used to express the kinds of compound leaves are as follows:

Unifoliate (for a single leaflet, as in orange and lemon where the compound leaf is greatly reduced and consists of one pinna attached to the petiole by a joint). Bifoliate for one with two leaflets; trifoliate for one with three leaflets, as in the clover; plurifoliate for many leaflets. Odd pinnate for a pinnate leaf with one or more pairs of leaflets and one odd leaflet at the end.

So leaves are palmately bifoliate, etc., pinnately bifoliate, etc. Decompound leaves are those where they are more than twice compound, as ternately decompound in the common meadow rue (Thalictrum).

Perfoliate leaves are seen in the bellwort (Uvularia), connate perfoliate, as in some of the honeysuckles where the bases of opposite leaves are joined together around the stem. Equitant leaves are found in the iris, where the leaves fit over one another at the base like a saddle.

[45] The most remarkable case is that of the “telegraph” plant (Desmodium gyrans). Aside from the day and night positions which the leaves assume, there is a pair of small lateral leaflets to each leaf which constantly execute a jerky motion, and swing around in a circle like the second hand of a watch.

[46] Seedlings are usually very sensitive to light and are good objects to study.

[47] For a fuller discussion of this subject by the author see Chapters XLVI-LVII of his “College Text-book of Botany” (Henry Holt & Co.).

[48] οῖκος = house, and λόγος = discourse.

[49] Term used by Schimper.

[50] See the author’s “College Text-book of Botany.” Chapter XLIX.

[51] ἔδαφος = ground.

[52] For a full discussion of forest societies see Chapter L in the author’s “College Text-book of Botany.”

[53] See Chapter LIV of the author’s “College Text-book of Botany.”