Hence the spores of ferns differ strikingly from the seeds of the higher plants in not containing the embryo radicle and cotyledons already formed, these being produced during or after germination; also in the fertilizing organs, viz. the antheridia or representatives of the anthers, and the archegonia or the representatives of the pistils, being produced from the cells of the prothallium.
The more minute of these structures are too difficult of observation and preparation for any one unaccustomed to microscopic manipulation, so that they have not been figured in detail; the figures given will, however, serve to guide the observer in their recognition.
Preservation.—The ferns may be easily preserved in the entire state, by laying them flat between sheets of coarse unsized paper, and subjecting them to moderate pressure in a screw-press; the paper should be changed, or dried before a fire every two or three days, and the pressure repeated until the specimens become dry and rigid. They may then be mounted on sheets of paper, being fastened either with thread passed round the stalk or portions of the frond with a needle, and tied in a knot behind, or with strips of paper gummed at the ends.
The minute structures may be preserved either in the dry state or in glycerine.
CHAPTER VI.
MOSSES, OR MUS´CI (MUSCUS, MOSS).
I NEED scarcely refer to the figures in [Pl. III.] to enable the reader to recognize the Mosses; every one knows them at once by their remarkably uniform general appearance, their miniature-plantlike form, their crowded little leaves, concealing the slender wiry stems, their growth in patches, and their curious urn-shaped fruits raised up on slender bristle-like stalks.
The leaves of the mosses are simple, i. e. not cut into segments, and consist of one or two layers of cells. The thinness of the leaves enables these cells to be seen very distinctly, the closely united cell-walls giving the leaves a netted or reticulated appearance (fig. 48), and the grains of chlorophyll being generally few and readily distinguished. The veins of the leaves, or the nerves as they are usually called, scarcely deserve the name; for neither they nor even the stems contain fibro-vascular tissue, but consist simply of elongate closely packed cells, and often the leaves have no nerves.
The fruit of the mosses consists of a capsule, sometimes called a sporan´gium (σπορἀ, seed, ἄγγος, vessel), usually placed at the end of a slender stalk, called the séta (seta, a bristle); but sometimes the stalk is absent or extremely short, when the capsule is said to be ses´sile (sessilis, sitting). The young capsule is covered with a thin extinguisher-like cap or calyp´tra (καλὑπτρα, a cover), which is carried up as the capsule and its stalk grow, so as to be either entirely thrown off, or to remain covering a greater or less portion of the capsule, when this attains maturity.
| PLATE III. [[PAGE 54.]] | |
| Mosses. | |
| Fig. | |
| 1. | Sphagnum acutifolium, expanded leaf. |
| 2. | Sphagnum acutifolium, cells of leaf. |
| 3. | Spermatozoa of Polytrichum piliferum. |
| 4. | Sphagnum acutifolium. |
| 5. | Sphagnum acutifolium, capsule. |
| 6. | Gymnostomum truncatulum. |
| 7. | Gymnostomum truncatulum, leaf. |
| 8. | Gymnostomum truncatulum, capsule and operculum. |
| 9. | Gymnostomum truncatulum, spore. |
| 10. | Dicranum heteromallum. |
| 11. | Dicranum heteromallum. |
| 12. | Dicranum heteromallum, leaf. |
| 13. | Dicranum heteromallum, operculum. |
| 14. | Dicranum heteromallum, calyptra. |
| 15. | Dicranum heteromallum, capsule; 15 a, peristome. |
| 16. | Tortula muralis. |
| 17. | Tortula muralis, leaf. |
| 18. | Tortula muralis, capsule; a, tooth of peristome. |
| 19. | Tortula muralis, operculum. |
| 20. | Tortula muralis, calyptra. |
| 21. | Tortula muralis, archegonia. |
| 22. | Polytrichum piliferum. |
| 23. | Polytrichum piliferum, leaf. |
| 24. | Polytrichum piliferum, calyptra. |
| 25. | Polytrichum piliferum, antheridial stems. |
| 26. | Polytrichum piliferum, single head. |
| 27. | Polytrichum piliferum, antheridia and paraphyses. |
| 28. | Funaria hygrometrica. |
| 29. | Funaria hygrometrica. |
| 30. | Funaria hygrometrica, leaf. |
| 31. | Funaria hygrometrica, capsule; a, operculum. |
| 32. | Funaria hygrometrica, stalk-like body. |
| 33. | Funaria hygrometrica, young archegone. |
| 34. | Funaria hygrometrica, more advanced archegone. |
| 35. | Funaria hygrometrica, section of young capsule. |
| 36. | Funaria hygrometrica, calyptra. |
| 37. | Funaria hygrometrica, antheridia. |
| 38. | Funaria hygrometrica, spores. |
| 39. | Funaria hygrometrica, annulus. |
| 40. | Funaria hygrometrica, archegonia. |
| 41. | Funaria hygrometrica, antheridial head. |
| 42. | Funaria hygrometrica, peristome. |
| 43. | Hypnum rutabulum. |
| 44. | Hypnum rutabulum, leaf. |
| 45. | Hypnum rutabulum, capsule. |
| 46. | Hypnum rutabulum, spores. |
| 47. | Hypnum rutabulum, peristome. |
| 48. | Hypnum rutabulum, cells of leaf. |
| 49. | Bryum capillare. |