IN TOUCH WITH NATURE

Otago Witness, Issue 3619, 24 July 1923, Page 6

IN TOUCH WITH NATURE

CRETACEOUS PL AXIS IX' NEW ZEALAND. By J. Dedmmond. F.L.S.. F.Z.S. Nine well-preserved fossil plants collected at \v aikato l lea (is oil the south side of the \\ aikato xtiver liave been ascribed to Neocomian times, equivalent to the Lower Cretaceous Period, which was fairly near the end of the Mesozoic, or Secondary Era, between the Palaeozoic or Early Life and the Cainozoic or Recent Life. Using the earth’s calendar supplied by physicists, computed on the rate at which lead is derived ircrn uranium, the flora now represented by these fossils grew perhaps BC,tXX),COO or 90,000,C00 years ago. Seven of the fossils are fern-like plants. It is believed that flowering plants did not appear until Cretaceous times. As there are onlv two flowering plant fossils in the collection, it is presumed that the old Waikato Heads flora was not later than the Lower Cretaceous. A particular palaeontological interest is attached to the two fossils of flowering plants, as they seem to be arnongst the earliest plants belonging to the group with two seed-leaves the dicotyledons, discovered in any part of the world. As a result of many hours’ patient search, the Rev. Brother Fergus, Sacred Heart College, Auckland, gathered from shales at South Head, near the fossil plant beds, specimens of an extinct cuttle-fish, known as belemnites, which are very plentiful there, together with about ten other fossils of extinct creatures of old-time seas. From Manakau Harbour to the Waikato River, in a belt averaging from five miles

to six miles wide, there stretch low hills. They form a straight coast-fine, twenty miles long and some SCO to 600 feet high, broken only by the narrow valleys of a few streams that run west. The land east of the belt rises gently and forms undulating country of solidified topography, its highest point being the yolcanic cone of Pukekohe Hill, about 710 feet high. Brother Fergus, for several reasons, believes that the hills once extended much further seaward than they do at present, several miles at least. He has geologised over an upland, 600 to 1200 feet above sea level, south of the Waikato River. It is deeply dissected by the valleys of streams, and the surface is very uneven, with few level tracts. Near the Kawa Stream, there is a pumice bed from 170 to 180 feet above sea level. He explains its presence by the theory that the material of which it is composed, was transported by the Waikato River from a pumice plateau through which it flows for a large part of its upper and middle courses, and that the material was deposited in a depression that formed a swamp’ on the borders of a large estuary of low-lying coastal land. Later the land was elevated, the pumice-bed was uplifted, and the river deepend its bed. He discards a suggestion that the pumice was transported from far distant localities by waves, because the character of the material and the bedding negative the suggestion. He ascribes the origin of the Manakau sand-dune range to a spit or a barrier beach that created a broad estuary of the Waikato River, and ascribes the origin of Manakau Harbour to streams, which, during a minor uplift, cut into silt deposits in the oh] Waikato Estuary. The area subsiding slightly, the sen penetrated the courses of the streams, and rapidly pushed back the low sea cliff 3.

The pretty, purple-flowered wild teasel, which, having introduced itself to New Zealand, has taken its permanent residence in some waste places in the North Island, is not included in Charles Darwin’s ‘‘lnsectivorous Plants,” but there seems to be no doubt that its tastes are carnivorous. At the bases of the large leaves on its main stem, there are cups. When the wild tease is in the perfection of its growth, and is flowering, the cups contain water, in which dead and putrefying insects and other tiny creatures may be found. The wild teasel’s habit of catching and retaining water in its cups was recorded by a British botanist some four hundred years ago. In mediaeval times, when strange beliefs were in vogue, the nasty liquor was collected, and was used, amongst other things, as a cure for bleary eyes and as a cosmetic, a practice which, perhaps, accounts for its popular title, ‘‘Venus’s Bath.” The teasel cup still is known in France as “une fontaine de Venus.” The plant’s official name, Dipsacus, suggests thirt-quneching Qualities. People who have tested these qualities state that the water, when quite fresh, is limpid, and not undrinkable. Many different classes of creatures are represented in those that pickle in the water. There are flies, beetles, ladybirds, plant-lice, spiders, earwigs, caterpillars, moths, butterflies, slugs and snails. In one cup were found six large beetles, from half an inch to three-quarters of an inch long, one fairly large caterpillar, and two flies. Strangely, there is only one record of a bee having got into a cup, and mosquitoes do not seem to take advantage of the ideal breeding-places the cups provide, although some species of mosquitoes habitually breed in (he putrescent liquor in pitcher-plants. The cups are adapted to serve as traps. In-

side they are glossy and smooth. Tiny creatures that have been led, by some inducement or other to enter a cup naturally, wdi slip down into the water at the bottom. and will find it difficult, perhaps impossible, to climb out. A beetle has been watched struggling to get out, and slipping down again and again. It is surmised, without any evidence to support the surmise, that the wild teasel exudes into the water a strong smelling or sweet-tasting toxic substance, which first attracts tiny creatures and then narcotises or intoxicates them. In that discreditable condition they fall in and get drowned. Experiments seem to show that insects at least are attracted and stupefied by the liquor. Slugs and snails, which could creep up a perpendicular window-pane, probably could have escaped if they had not imbibed. Dainty butterflies that had a “spot” from a cup seemed to be unmistakably under the influence. The absence of bees from the cups is accounted for by the theory that they are. clean feeders, and have a distaste for putrescent liquor, and do not, as a rule, get drunk. It is an easy step from the observations and experiments, especially in these days of utilitarian reasoning, to the theory that the wild teasel absorbs and digests the highly nitrogenous liquor in the cups, and benefits by it. Until observations of (he nature and functions of filaments protruded by the plant are complete, it cannot be said that the nitrogen-charged liquid actually is absorbed, but there seems to be no doubt that the plant is carnivorous. In it there have been found almost all the characteristic features found in other plants that are recognised as carnivorous. If this theory is accepted, the wild teasel will rank

as one of the biggest carnivorous plants known to botanists; and, as far as is known, no other plant captures such large insects as those found in the wild teasel’s cups. Sundews, which grow plentifully in boggy places in high country in New Zealand, notably in Arthur’s Pass, Canterbury, exude a sweet, sticky substance on their* leaves, which curl over cud cover and digest insects caught in the substance, but those insects are very small, and the sundew’s methods are widely different from those the wild teasel is believed to use.