Juncus or Juncaceae) are widely diffused over the world, and certainly many of their species have very wide ranges--in short, it seems that my question is whether there is any relation between the ranges of genera and of individual species, without any relation to the size of the genera. It is evident a genus might be widely diffused in two ways: 1st, by many different species, each with restricted ranges; and 2nd, by many or few species with wide ranges. Any light which you could throw on this I should be very much obliged for. Thank you most kindly, also, for your offer in a former letter to consider any other points; and at some future day I shall be most grateful for a little assistance, but I will not be unmerciful.
Swainson has remarked (and Westwood contradicted) that typical genera have wide ranges: Waterhouse (without knowing these previous remarkers) made to me the same observation: I feel a laudable doubt and disinclination to believe any statement of Swainson; but now Waterhouse remarks it, I am curious on the point. There is, however, so much vague in the meaning of "typical forms," and no little ambiguity in the mere assertion of "wide ranges" (for zoologists seldom go into strict and disagreeable arithmetic, like you botanists so wisely do) that I feel very doubtful, though some considerations tempt me to believe in this remark. Here again, if you can throw any light, I shall be much obliged. After your kind remarks I will not apologise for boring you with my vague queries and remarks.
LETTER 315. TO J.D. HOOKER. Down, December 25th [1844]. Happy Christmas to you.
(315/1. The following letter refers to notes by Sir J.D. Hooker which we have not seen. Though we are therefore unable to make clear many points referred to, the letter seems to us on the whole so interesting that it is printed with the omission of only one unimportant sentence.
The subjects dealt with in the letter are those which were occupying Hooker's attention in relation to his "Flora Antarctica" (1844).)
I must thank you once again for all your documents, which have interested me very greatly and surprised me. I found it very difficult to charge my head with all your tabulated results, but this I perfectly well know is in main part due to that head not being a botanical one, aided by the tables being in MS.; I think, however, to an ignoramus, they might be made clearer; but pray mind, that this is very different from saying that I think botanists ought to arrange their highest results for non-botanists to understand easily. I will tell you how, for my individual self, I should like to see the results worked out, and then you can judge, whether this be advisable for the botanical world.
Looking at the globe, the Auckland and Campbell I., New Zealand, and Van Diemen's Land so evidently are geographically related, that I should wish, before any comparison was made with far more distant countries, to understand their floras, in relation to each other; and the southern ones to the northern temperate hemisphere, which I presume is to every one an almost involuntary standard of comparison. To understand the relation of the floras of these islands, I should like to see the group divided into a northern and southern half, and to know how many species exist in the latter--
1. Belonging to genera confined to Australia, Van Diemen's Land and north New Zealand.
2. Belonging to genera found only on the mountains of Australia, Van Diemen's Land, and north New Zealand.
3. Belonging to genera of distribution in many parts of the world (i.e., which tell no particular story).
4. Belonging to genera found in the northern hemisphere and not in the tropics; or only on mountains in the tropics.
I daresay all this (as far as present materials serve) could be extracted from your tables, as they stand; but to any one not familiar with the names of plants, this would be difficult. I felt particularly the want of not knowing which of the genera are found in the lowland tropics, in understanding the relation of the Antarctic with the Arctic floras.