Species Of Araucaria Research Articles

Araucariaceae as indicators of climate and paleolatitudes

Mesozoic Araucariaceae dominated in the low-latitude (15–20°N) belt of summer-dry climate. It is suggested, that araucarian forests were the most thermophilous Mesozoic assemblages. There were no equivalents of the modern tropical rain forest. In the middle latitudes, Araucariaceae shared dominance with Elatides and Classopollis-producing plants. The northernmost Triassic records of Arauariaceae on both eastern and western Pacific coasts are at 35°N; in the Jurassic and Cretaceous time they are constantly at about 50°N. These climatically controlled chrological features are oblique to the paleolatitudes inferred from paleomagnetic data. On the basis of material from the Jurassic of Mali, a new species of Araucaria is described, viz. Araucaria africana sp. nov.

Size-Composition and Regeneration of Araucaria Stands in New Guinea

Two species of Araucaria are widespread in primary forests in Papua New Guinea. A. cunninghamii D. Don, which also occurs in Irian Jaya and eastern Australia, is found growing naturally between 600 m and 2800 m altitude (mostly 900-2200 m), usually associated with steep slopes and ridges. A. hunsteinii K. Schumann, which is confined to Papua New Guinea, is found between 550 m and 2100 m (mostly 750-1500 m) and is characteristic of less steep slopes. A survey of all known localities has recently been published (Gray 1973). Natural stands of both species have been utilized for timber extraction in several areas. In addition both species have been extensively employed in reforestation and as ornamentals. Despite the large number of trees cut annually there is very little precise information available on the actual heights and girths commonly attained. Many of the recorded heights are unreliable since they were generally estimated by indirect methods, for example with the Blume Leiss hypsometer, which may be subject to considerable error when used on steep terrain. The first part of this paper reports numerous direct measurements on felled specimens and the two Araucaria species are shown to be among the tallest trees in the tropics. These trees are of considerable economic importance and significant policy decisions have been taken in recent years on their culture. Thus the Department of Forests has ceased planting A. cunninghamii and changed from clear felling and open planting to enrichment planting with A. hunsteinii in the major plantations in the Bulolo-Wau-Watut valleys (longitude 146? 35' E, latitude 70 13' S). Yet there is a dearth of information on the size-composition of natural stands and on natural regeneration. The only substantial published reports (Havel 1971; Paijmans 1970) concern A. hunsteinii and even these are incomplete in respect of seedling measurements and records of associated species. The second part of this paper documents in detail populations of both species in extensive stands in the Bulolo-Wau region.

The presence of 3- O-methylrhamnose in araucaria resinous exudates

The comparatively rare sugar 3- O-methylrhamnose has been detected in the polysaccharide components of the resinous exudates from five Araucaria species, and it appears to act as a useful chemical marker in gymnosperms.

An analytical study of gum exudates from the genus Araucaria jussieu (gymnospermae)

Analytical data are presented for the gum polysaccharides isolated from the resinous exudates from five Araucaria species; for three of these, two specimens from different geograpphical locations have been studied. The data are compared with those available for the only Araucaria species examined previously. The results indicate that the analytical differences between species of this Gymnosperm genus are not so great as are known to occur in genera of the Angiospermae.

The Social Status of Agathis in a Rain Forest in Melanesia

Of the small group of conifers which occur in the lowland tropics species of Agathis, Dacrydium and Podocarpus grow mixed with angiosperms in tropical rain forest. Dacrydium and Podocarpus are predominantly montane genera with a few species descending into the lowlands, Agathis has rather more lowland species. In its present distribution (Florin 1963) and habitat Agathis is the most euthermic confer. Mixed conifer-angiosperm forests occur scattered through Malesiat and the southwest Pacific region. Their ecology has scarcely been investigated: this is important because of its bearing on the evolutionary history of the relationships between conifers and angiosperms. Further, tropical conifers, like temperate ones, are sometimes associated with podsolic soils and a study of them might be expected to throw light on the phenomenon of podsolization in the tropics. The temperate podocarp-angiosperm forests in New Zealand, and the forests of Queensland and New Guinea where species of Araucaria grow as emergents from an under-layer of Tropical Lowland and Lower Montane Rain Forest, have received some attention from ecologists. The native vegetation of much of the lowlands of New Zealand is a series of forests which range from pure angiosperm through angiosperm-podocarp mixture to pure podocarp. The main podocarp is Dacrydium cupressinum Soland. There are various hypotheses to explain this series, which Robbins (1962) has summarized. Cockayne considered that it represents an ecological succession, leading from conifer forest to angiosperm forest climax. Poole and Holloway later both suggested alternation of the forest types on any one site. Holloway later abandoned this explanation and suggested that a climatic change about 800 years ago had favoured the angiosperms and was leading to replacement of the conifers, still incomplete. Robbins himself postulated that there are two forest types, an ancient conifer forest and a geologically more recent angiosperm forest; both are found in pure form but in many places they have fused and the angiosperms are exercising a progressive supremacy over the conifers (Robbins 1962). Agathis australis Salisb. occurs in the north of New Zealand around Auckland. Apparently it does not regenerate in its own shade and in the climax vegetation is replaced by other species (Cockayne 1928, p. 127; Mirams 1957). According to Mirams (1957) it invades the secondary vegetation which springs up after clearing and at one stage in the secondary succession is well represented by all size classes; the big trees in

Structure and seasonal study of the shoot apex of two species ofAraucaria

The shoot apices ofAraucaria columnaris andA. bidwillii exhibit a tunica-corpus organization. In the former the tunica is one-layered during spring and summer months and becomes more stratified during winter months. InA. bidwillii it is usually two-layered, with a tendency to further stratification.

Tertiary Araucariaceae From South-Eastern Australia, With Notes on Living Species

The foliage shoots, male cones, and female cone-scales of a new Tertiary species of Araucaria, section Eutacta, from the brown coal at Yallourn, Victoria, have been described; leaves and male and female cones possessing the general features that characterize species of Agathis have been identified. Leaves of a second species of Agathis have been distinguished in a bed associated with the brown coal at Bacchus Marsh, near Melbourne, Vic.

Notes on Two Species of Araucaria in New Guinea and a Proposed New Section of the Genus

Notes on Two Species of Araucaria in New Guinea and a Proposed New Section of the Genus

Habitats of Araucarias and Changes of Climate

IN Science News-Letter, Feb. 18, 1928, referred to in NATURE of Aug. 18, p. 257, the statement is made, on the authority of Dr. R. W. Chaney, that “the living Araucaria species all prefer cool, rather dry habitats”. This statement was the main reason given for the conclusion that the Gobi region of Manchuria had a dry, rather cool climate in the Cretaceous period when the dominant trees were Araucarias.

Notes on the Resins of two Queensland species of Araucaria.

Notes on the Resins of two Queensland species of Araucaria.

New Trees and Shrubs for English Plantations*

WITHIN the last twenty years a complete revolution has taken place in the character of our out-of-door planting of ornamental trees and shrubs; trees which twenty years ago were rarities that a lover of arboriculture would go miles to see, are now to be met with in every gentleman's shrubbery or lawn with any pretensions to artistic arrangement. A really good hand-book was greatly wanted, to enable a planter to choose the species best suited to the climate, and best adapted to the special circumstances of his own particular estate. Such a handbook Mr. Mongredien's “Planter's Guide” proposes to furnish, and to a great extent successfully. The plan of the book is admirable. We first have a list of 621 species of trees and shrubs, “selected from the large multitude which from time to time have been introduced from all parts of the world, and of which the vast majority are not worth cultivation for ornamental purposes.” A brief description accompanies each name, with instructions as to the best aspect or position, and other needful particulars. These 621 species are then looked at from different points of view, and in the second part are classified accordingly: first, as to their height, then as to their foliage, next as to their flowers, and finally as to their fruit. Furthermore, we have selected lists of species remarkable for singularity of aspect, for rapidity of growth, suitable for hedges, thriving under the drip of trees or in the smoke of cities, adapted for different soils, &c. On looking closer into the manner in which this programme is carried out, we certainly find defects, as might be expected in a work which covers so much ground; but the defects are such as the author is sure to have brought under his notice, and which may easily be remedied in a second edition. Thus, although the list seems an extensive one, we miss many species, either old favourites or newly introduced, which ought to have had a place in it for their beauty or their useful properties: such as, among flowering shrubs, the Berberis aquifolium, a desideratum in every shrubbery, from its early flowering and the beautiful gloss of its evergreen leaves; B. vulgaris, the scarlet fruit of which is one of the most beautiful ornaments for the table; and the butcher's broom, Ruscus aculeatus, very easy of cultivation, and striking from the weirdness of its appearance, and the very peculiar growth of its flowers: and among climbing-plants, the common hop, used in some of the London parks in a very graceful manner to cover the stems of the poplar-trees. The list of plants thriving in the smoke of cities might also have been more than doubled by any of the author's friends who happen to have a London suburban garden. The illustrations interspersed here and there are very pretty; the frontispiece, however, a magnificent specimen of Araucaria imbricata, is unfortunate. If really taken from that tree, and not from another species of Araucaria not mentioned in Mr. Mongredien's list, it is very badly drawn.

LIV.—On a new species of Araucaria from New South Wales; and on Nuytsia floribunda

(1842). LIV.—On a new species of Araucaria from New South Wales; and on Nuytsia floribunda. Annals and Magazine of Natural History: Vol. 8, No. 53, pp. 438-439.