As contrasted with the extreme scarcity of peculiar species among the flowering plants, it is the more interesting and unexpected to find a considerable number of peculiar mosses and Hepaticæ, some of which present us with phenomena of distribution of a very remarkable character. For the following lists and the information as to the distribution of the genera and species I am indebted to Mr. William Mitten, one of the first authorities on these beautiful little plants. That of the mosses has been corrected for this edition by Dr. R. Braithwaite, and several species of hepaticæ have been added by Mr. Mitten.
List of the Species of Mosses and Hepaticæ which are peculiar to the British Isles (or not found in Europe).
(Those belonging to non-European genera in Italics.)
| Mosses. | ||
| 1. | Systegium Mittenii | South England. |
| 2. | Campylopus Shawii | North Britain. |
| 3. | ,, setifolius | Ireland, Wales, and Hebrides. |
| 4. | Seligeria calcicola | South England. |
| 5. | Pottia viridifolia | South England. |
| 6. | Leptodontium recurvifolium | Ireland and Scotland. |
| 7. | Tortula Hybernica | Ireland. |
| 8. | Streptopogon gemmascens | Sussex. |
| 9. | Bryum barbatum | Scotland. |
| 10. | Bartramidula Wilsoni | Ireland, Wales, and Scotland. |
| 11. | Daltonia splachnoides | Ireland, Antilles, and Mexico. |
| 12. | Hookeria laetevirens | Ireland, Cornwall, and Madeira. |
| 13. | Hypnum micans | Ireland. |
| 14. | Myurium Hebridarium | Hebrides and Atlantic Islands. |
| 15. | Hedwigia ciliata var. striata | Wales and Scotland. |
| Hepaticæ. | ||
| 1. | Frullania germana | Ireland. |
| 2. | ,, Hutchinsiæ | Ireland, Scotland, Wales, Devon, Tropical regions. |
| 3. | Lejeunia flava | Ireland, Atlantic Islands, S. America, Africa, &c. |
| 4. | ,, microscopica | Ireland, Wales, Cumberland, Madeira. |
| 5. | ,, Holtii | Ireland (Killarney). |
| 6. | ,, diversiloba | Ireland (Killarney), Mexico? |
| 7. | ,, patens | Ireland. |
| 8. | Radula tenax | Ireland. |
| 9. | ,, Holtii | Ireland. |
| 10. | ,, voluta | Ireland, Wales, Cumberland, Mexico? |
| 11. | ,, Carringtonii | Ireland. |
| 12. | Lepidozia Pearsoni | Wales. |
| 13. | Adilocolia decipiens | Ireland, Wales, Africa, and S. America. |
| 14. | Cephalozia aeraria | Wales. |
| 15. | Lophocolia spicata | Ireland, Cornwall, Anglesea. |
| 16. | Martinellia nimbosa | Ireland (Brandon Mountain). |
| 17. | Plagiochila spinulosa | Wales, Ireland, and Scotland, Atlantic Islands. |
| 18. | ,, ambagiosa | Ireland, India. |
| 19. | Jamesoniella Carringtonii | Scotland. |
| 20. | Gymnocolea Nevicensis | Scotland. |
| 21. | Jungermannia Doniana | Scotland. |
| 22. | Cesia crenulata | Ireland, Wales. |
| 23. | Chasmatocolea cuneifolia | Ireland. |
| 24. | Aerobolbus Wilsoni | Ireland, S. America, New Zealand. |
| 25. | Petalophyllum Ralfsii | Ireland, Cornwall, Devon. |
Many of the above are minute or obscure plants, and are closely allied to other European species with which they may have been confounded. We cannot therefore lay any stress on these individually as being absent from the continent of Europe so much of which is imperfectly explored, though it is probable that several of them are really confined to Britain. But there are a few—indicated by italics—which are in a very different category; for they belong to genera which are altogether unknown in any other part of Europe, and their nearest allies are to be found in the tropics or in the southern hemisphere. The four non-European genera of mosses to which we refer all have their maximum of development in the Andes, while the three non-European Hepaticæ appear to have their maximum in the temperate regions of the southern hemisphere. Mr. Mitten has kindly furnished me with the following particulars of the distribution of these genera:—
Bartramidula. Asia, Africa, S. America and Australia, but not Europe or N. America.
Streptopogon is a comparatively small genus, with seven species in the Andes, one in the Himalayas, and three in the south temperate zone, besides our English species.
Daltonia is a large genus of inconspicuous mosses, having seventeen species in the Andes, two in Brazil, two in Mexico, one in the Galapagos, six in India and Ceylon, five in Java, two in Africa, and three in the Antarctic Islands, and one in Ireland.
Hookeria (restricting that term to the species referable to Cyclodictyon) is still a large genus of handsome and remarkable mosses, having twenty-six species in the Andes, eleven in Brazil, eight in the Antilles, one in Mexico, two in the Pacific Islands, one in New Zealand, one in Java, one in India, and five in Africa—besides our British species, which is found also in Madeira and the Azores but in no part of Europe proper.
These last two are very remarkable cases of distribution, since Mr. Mitten assures me that the plants are so markedly different from all other mosses that they would scarcely be overlooked in Europe.
The distribution of the non-European genera of Hepaticæ is as follows:—