Page:Journal of botany, British and foreign, Volume 34 (1896).djvu/225

 JUNCUS TENUIS WILLD. IN NOKTH WALES. 203 as far as Argentina, and across the continent from Newfoundland to Vancouver Island. 2. As already pointed out by Mr. Bennett, its habitats are more various than the European ones. The following are a few quoted from American floras, or from specimens in the British Museum or Kew Herbaria: — "Low grounds," ''roadsides," "meadows and damp pastures," " boggy pastures," "old roads in woods," "ditches and river-sides," &c. 3. The following records of altitude show that, after making allowance for difference of latitude, it has a greater vertical range there than in Europe : — Colorado, hot springs, 5500 ft. (Jones, spec, in Brit. Mus.). Black Hills, Dakota, 3500 ft. {Rynherg, spec, in Kew Herb.). San Luis Potosi (22° N. lat.), 6000-8000 ft. (Parry d Palmer, spec, in Kew Herb.). S. Mexico, 7500 ft. (Biol. Centr. Amer. Bot. iii. 399). 4. The most striking fact of all is the great variability of the plant in America. Engelmann (Bot. Works, 251) shows that this variability is exemplified "in the size of the plant (from a few inches to two feet), in the size and fulness of the inflorescence, and in the size and development of the one, two, or even three spathes." This author describes two varieties, viz., secundiis and congestus. Watson (Geol. Survey Calif. Bot. ii.) states that the latter var. is the prevalent form of the plant on the Californian coast. In addition to these, a third var. (platycaulos Fr. B.) is described from S. America. All the above observations seem to point out America — probably N. America — as the home of J. tenuis, and the great difference between its mode of distribution there and in Europe strengthen the conviction that in the latter continent it is a recent arrival. In 1878 Cheeseman recorded the plant from New Zealand (Trans. New Zeal. Inst. ii. 433). He says the plant was " abundant in some marshy ground not far from the bank of the river, but, curiously enough, during the hurried examination I was able to make of the Wairoa district I did not observe it either higher up or lower down the river, although suitable localities are sufficiently abundant." In the same note the author seems inclined to accept the plant as indigenous, but in a subsequent paper on the naturalized plants of Auckland (Trans. N. Z. Inst. xvii. 293) he gives five localities, and adds, " I am now inclined to consider the species as an importation (Europe)." It may be added that J. invoiucratus T. Kirk [Trans. N. Z. Inst. 1877, 550), from South Island, has been reduced by Buchenau to J. tenuis. In the Botany of the Challenger, 154, a rush brought from Tristan-da- Cunha, the specimens of which were imperfect and which had been collected in boggy pastures, is named J. tristanianus Hemsley, and regarded as endemic. This also is said by Buchenau to be nothing more than J. tenuis. If this is correct (and botanists who see the specimen in the Kew Herbarium will probably agree with the reduction), the interesting question arises whether the plant is a recent introduction here also. We know that Cerastium triviale, Oxalis corniculata, Senecio vulgaris, Rumex Acetosella, and several others, have succeeded in establishing themselves on the