NATURALISTS' FIELD CLUB

Otago Daily Times, Issue 18612, 21 July 1922, Page 2

NATURALISTS' FIELD CLUB

EXCURSION! TO PUDDING ISLAND. On Saturday afternoon a large gathering of members of the Naturalists* Field Club journeyed to Pudding Island— a small island in Otago Harbour, hear Pbrtobello. The low tide, by exposing a wavered rook platform entirely surrounding the island, made observation of its sides easy. The rock of the island is entirely trachyte, similar to that of the Portobello Peninsulo, and, like it, very, much divided by numerous trachyte dykes of all thicknesses and in all directions. It shows, also, very markedly the concentration of red ferruginous matter into .concentric shells containing the whiter trachyte. The top' of the island is quite flat, due no doubt to human agency rather than natural processes. A bar of sand gravel connects the island to the mainland, and indicates that the tidal currents sweep in from both ends of the channel at the same time. The margin of the island is much indented, due to differential erosion of the dykes, which are usually much softer than the body rock, and many small caves are formed in the same way. , There is a wealth of vegetation on the r summit, and investigations were confined to the botanical section. Special interest attaches to this area from the fact that it has not been subjected to the attentions either of sheep or rabbits; hence it was not surprising to find there a native cress (Lepidium oleracenm), which is fast disappearing from the mainland. Indeed, very few exotic plants have gained a hold on this island (only 16 wore noted), ttaugH some 90 species of native plants still clothe its surface, apart from those that some misguided enthusiast has seen fit to introduce. Among the latter were a native birch and the following olearias:—O. Traversii, O. icifolia, O. macrodonta, O. virgata, and 0. Foster!, besides Senocio eleagnifWiua and the common flax. The greater part of the vegetation consists of low forest growth, save on tho south side, The trees that give the superficial facies to it being principally the ngaio and the mapau. This forested area is surrounded by a zone of shrubs of considerable variety, though there is little undergrowth in the bush itself. Tho more conspicuous plants other than the two named include the grass tree (Dracophyllum), totara, mingi-mingi (Styphelia aoerosa), ateake (Olearia avicenniaefolia), koromiko, shore speedwell (veronica elliptioa), breadleaf, and coprosma crossifolia. Tho native iris was in full berry, and was much admired. One of the five sedges of the island was remarkable in having fruit stalks 10ft long. Other plants to which special attention should be drawn were the climbing anise (Angelica geniculata), the native thistle (Sonclius asper), the toad-rush (Cladium vauthtera), and the Atriplex patula. Among ferns, the varieties of tho coastal spleonworts found here would in themselves furnish material for much investigation. NATURE PHOTOGRAPHY. The fortnightly indoor meeting, hold on Monday evening, was well attended, and was presided over by Mr Angel. Four new members were elected. Section leaders gave interesting reports on Saturday’s outing, and a nuijiber of entomological specimens were passed round for examination. The chief business of tho evening was an address by Mr Barland on "Nature Photography.!’ The lecturer equipped himself with sufficient apparatus and photographs to make his subject intensely interesting and instructive ,to even the most inexperienced, but perhaps tho keenest interest was displayed! when, fie explained that quite a simple method is available for those who have no camera, but wish to record impressions of leaves, fern 'fronds, or anything that may bo pressed flat without distortion. All that is necessary is to press the specimen, till quite dry and flat. Then take an ordinary photographic printing frame with a piece of clean glass in it, lay the specimen on the glass, then a piece of printing out paper, back up with’ blotting paper, and then put the back of frame in position and fasten. All is then ready to make a print, and this m»y be done either by daylight or artificial light. If self-toning paper is used for daylight printing, then the print only needs fixing and washing. If gaslight paper is preferred, then, of course, the paper will be developed and fixed and washed. This method produces a negative print. This is as far as many go in the process, but it may be carried further, and the negative print be used to print from and so produce a positive. In many cases this will be an improvement. Mr Earland also gave some valuable hints on the best methods cf photographing objects in Nature by stereoscopy. His lecture was fully illustrated with practical examples of photographic art, and at its conclusion he was accorded a hearty vote of thanks. It was decided that the outing for July 29 would be at tho Soldiers’ Cairn, Highcliff.