The obvious use of seeds is the distribution of the species by the formation of new individuals.
In the general outline which has been given of the elements, tissues, and organs of plants, they have been examined principally as existing in the higher groups, or those of more complex structure; and to enter further upon a description of these plants would involve the consideration of variations in the form and arrangement of the organs of which they are composed. As these can mostly be investigated without the use of the microscope, we must pass to those in which the entire plant consists of little more than simple or parenchymatous cells, and in which the representatives of the flower are so inconspicuous, or are reduced to so elementary a condition, that the plants included in the Division have been termed Cryptogam´ic (κρυπτὀς, concealed, γἁμος, union—figuratively for reproductive organs) or Flowerless Plants. The reproductive organs of the Cryptogamia are usually termed the fructification, implying that they produce fruit, but not flowers.
| PLATE II. [[PAGE 49.]] | |
| Ferns and Lichens. | |
| Fig. | |
| 1. | Chlorococcum vulgare. |
| 2. | Parmelia parietina. |
| 3. | Parmelia parietina, section of a saucer (apothecium). |
| 4. | Parmelia parietina, gonidia and asci. |
| 5. | Parmelia parietina, asci and paraphyses; 5 a, spores. |
| 6. | Calicium clavellum. |
| 7. | Calicium clavellum, stalked apothecia. |
| 8. | Calicium clavellum, apothecium. |
| 9. | Polypodium vulgare, frond. |
| 10. | Polypodium vulgare, lobe of frond. |
| 11. | Polypodium vulgare, group of capsules (thecæ). |
| 12. | Polypodium vulgare, capsule and spores. |
| 13. | Polypodium vulgare, spore germinating. |
| 14. | Polypodium vulgare, prothallium. |
| 15. | Polypodium vulgare, portion of prothallium, with archegonia. |
| 16. | Aspidium filix mas, frond. |
| 17. | Aspidium filix mas, pinnules with sori. |
| 18. | Aspidium filix mas, single pinnule. |
| 19. | Scolopendrium vulgare, frond. |
| 20. | Scolopendrium vulgare, portion of frond. |
| 21. | Cladonia coccifera. |
| 22. | Cladonia cornuta. |
| 23. | Cladonia pyxidata. |
| 24. | Cladonia rangiferina. |
| 25. | Cladonia rangiferina, ends of podetium. |
| 26. | Graphis scripta. |
| 27. | Graphis scripta, lirellæ. |
| 28. | Graphis scripta, asci and spores. |
| 29. | Graphis scripta, spore. |
| 30. | Opegrapha betulina. |
| 31. | Opegrapha betulina, lirellæ. |
| 32. | Opegrapha betulina, lirella. |
| 33. | Opegrapha betulina, ascus with spores. |
| 34. | Scalariform ducts of Brake (Pteris). |
