Page:Journal of botany, British and foreign, Volume 34 (1896).djvu/224

 JUNCUS TENUIS WILLD. IN NOKTH WALES. Harlech, and 3 miles from the sea, along a disused bye-road con- necting the Harlech and Dinas roads. The locality is hilly, the altitude being about 600 ft. above sea level. The rush is found in isolated tufts in the beaten track running along the middle of the road. In no case did I find any plants along the sides of the road or in the neighbouring fields. The soil is loamy. It flourishes well on an exposed part of the road, thirty to forty yards long, where the soil is dry and thin. It attains a larger size in the more moist parts of the road, but the tufts are fewer in number." These habitats bear a curious and striking resemblance to those described by Mr. Scully (Joura. Bot. 1887, 335). In one case he says that the plant grew "within a few yards of the sea, and quite near such maritime plants as C. distans, C. extensa, J. Gerardi; the latter were within tidal influence, while J. tenuis was just outside its reach." This would exactly apply to the Portmadoc locality, while the other habitat bears an equally striking resemblance to the Harlech one, both being old grassy hill-roads. The conclusions that seem to present themselves from a study of the Portmadoc and Prenteg localities are — 1. That here at least the plant is undoubtedly a recent intro- duction. It may of course have spread from a neighbouring locality ; when, however, we consider that indigenous plants which are rare are generally in process of dying out, it seems far more probable that a plant which spreads so readily as J. tenuis seems to do is a recent introduction from a foreign country. 2. Its strikingly erratic distribution and its disappearance as soon as the grass is allowed to grow freely about it lend colour to the view that it is not a native. 3. The partiality of the plant for cattle-paths suggests that cattle may be the means of distributing the seeds. The plant is very probably a native of N. America. May not the seeds have been carried over with cargoes of corn ? If so, we can easily under- stand their becoming attached to the feet of cattle. Those that happened to have dropped off in fairly open places would suc- ceed in growing, while such as were left in the thick pasture would be stifled by the herbage, or remain dormant until the grass happened to be sufficiently trodden down to give them a chance of growing. A study of the distribution of J. tenuis in other parts of the world seems to confirm the view that it is a foreign introduction in this country. As shown by Mr. Bennett, continental botanists are much divided on this question. This uncertainty is in itself an argument in favour of its not being indigenous. Buchenau, in his monograph of the Juncacece {Enr/l. Bot. Jahih. 1890, 193) says that in Middle Europe it was formerly only known from a few localities, but that within the last decade it has considerably extended itself. These remarks are certainly significant. The distribution of the plant in America is strikingly different from the above — 1. It is one of the most common and best known, ranging from the Peace River through Mexico and the W. Indies to S. America