Warts

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Warts
New Zealand warthog (Dacrycarpus dacrydioides)

New Zealand warthog ( Dacrycarpus dacrydioides )

Systematics
Department : Vascular plants (tracheophyta)
Subdivision : Seed plants (Spermatophytina)
Class : Coniferopsida
Order : Conifers (Coniferales)
Family : Stonecaceae (Podocarpaceae)
Genre : Warts
Scientific name
Dacrycarpus
( Endl. ) De foliage.

The warthog ( Dacrycarpus , syn .: Podocarpus sect. Dacrycarpus , Podocarpus sect. Dacrydium ) are a genus of plants with nine species in the family of the stone ennae family (Podocarpaceae) within the conifers (Coniferales). Their distribution area extends from Southeast Asia via New Guinea to New Zealand . There are numerous fossil finds , the oldest dating from the Eocene and at least 40 million years old.

features

Female seed cones of Dacrycarpus dacrydioides with a red-orange podocarpium and seeds surrounded by blue-violet epimatium

Dacrycarpus species are dioecious , rarely single, sexually separated , evergreen shrubs or trees. Trees usually have a single straight, often cylindrical trunk that is knotless up to half its height or more. The trunk bark is hard, occasionally shows cork pores and is scaly on older trees. The treetop is initially conical, later cylindrical and in old trees it is open and flat to dome-shaped. The branches are green at least in the first year and are grooved between the leaf bases. Two types of shoots are formed: short shoots, which only show a growth spurt, usually only appear on young trees and have elongated leaves, and long shoots, which grow continuously, have leaves and the majority of the branches form older trees.

The wood is hard, heavy and not fragrant compared to that of other softwoods. The heartwood is pale to light yellow and merges into the wide, cream-colored sapwood. The grain is fine and even, there are no resin channels.

Three types of leaves are formed: small scale leaves, needle-shaped leaves (needles) and flattened, linear-sickle-shaped leaves. All three are arranged in a spiral, running down from the base, pressed down to protruding far and form resin channels. The linear, sickle-shaped leaves are only found in some species, they grow in two rows on young plants or on the lateral branches of older trees and bushes. The small scale leaves grow in some species on cone-bearing branches and on lateral vegetative branches, other species have needle-like leaves in the same places. These two leaf types do not grow in two rows and are pressed to protrude. Both leaf sides show stomata .

The pollen cones grow individually or in pairs on axillary, short stems. They are almost spherical at first, but later lengthen and are then short cylindrical, about 10 millimeters long and 3 millimeters in diameter. The microsporophylls grow in a spiral on a thin axis. They have triangular tips and two pollen sacs each, which contain the pollen provided with three air chambers.

The seed cones stand individually and upright on axillary, short stems overgrown with scale leaves. They are often encased in needle-shaped leaves that grow at the base of the cones. The pegs form resin channels. They form several spirally arranged cover scales, whereby only one to three, sometimes four, are fertile and usually only one scale near the end of the axis is fertilized and forms a seed. The unfertilized scales grow together and form a wrinkled podocarpium , which is succulent and red or purple in color when ripe. The seed is completely surrounded by the soft epimatium , which is partially fused with the fertile bract.

Seedlings form two cotyledons with two leaf veins each. The basic chromosome number is x = 10.

distribution

The range of the nine species extends in Southeast Asia from South and Southwest China to Myanmar and Indochina to the Malay Peninsula and further to New Ireland , New Guinea and in the Southwest Pacific to New Caledonia , Vanuatu , Fiji and New Zealand .

Botanical history

Today representatives of Dacrycarpus are mainly found in tropical areas, with the exception of Dacrycarpus dacrydioides , a species that occurs in the mildly temperate climate of New Zealand . However, there are numerous fossil recordings of leaves, particularly in the southwestern Pacific, almost exclusively from areas that are now temperate. The oldest finds come from the Eocene of South America, the southeast of Australia and Tasmania and are around 40 million years old or older, all areas in which the genus no longer occurs today. Even older finds could not be clearly assigned and could be more closely related to the genus Dacridium . The fossil finds from Australia are particularly rich, showing a continuous decrease in leaf size, which is seen as an adaptation to a climate that is becoming drier. In Australia, the species appears to have been extinct in the Miocene around 20 million years ago. In Tasmania, however, there are finds up to the beginning of the Ice Age in the Pleistocene 2 million years ago, but the assignment of the most recent finds is doubtful. In New Zealand the first representatives seem to have arrived late, the earliest finds are from the Miocene , and there are relatively few of them compared to the wide distribution today.

Systematics

The warts disks ( Dacrycarpus ) are a genus in the family of stone disks, order (Coniferales). In 1848 Stephan Ladislaus Endlicher set up the section Dacrycarpus as part of the genus Podocarpus , in 1969 David John de Laubenfels raised the taxon to a genus of its own. The genus name Dacrycarpus comes from the Greek, dakryon means "tear" and karpos stands for "fruit".

The warty disks differ from other representatives of the stone vein family by the merging of the fertile cover sheet of the seed cones with the seed scales, which together form a comb-like structure on the side of the epimatium and end in a lateral beak. However, they also show similarities with other genera. The pollen has three air chambers that are otherwise only found in the genera Microcachrys and Microstrobos . The warty podocarpium and the laterally flattened leaves of young trees, on the other hand, are both found in the genus Acmopyle . The leaves of older trees, however, are similar to those of the genus Dacrydium , which is also reflected in the scientific genus name. Genetic studies also show that the genus is closely related to Dacrydium and Falcatifolium , and is also closely related to Acmopyle , Microstrobus , Microcachrys and Podocarpus .

Nine species are assigned to the genus of the warthog ( Dacrycarpus ), listed here with a key according to Aljos Farjon :

  • Dacrycarpus cinctus (Pilg.) De Laub. : All leaves have the same needle-shaped shape, 1.6 to 6, rarely up to 10 millimeters long and 0.4 to 0.8 millimeters wide. The leaves at the base of the seed cones are 6 to 11 millimeters long, curved inward and enclose the podocarpium and also parts of the seed.
  • Dacrycarpus compactus (Wasscher) de foliage. : All leaves have the same needle-shaped shape and are sometimes slightly S-shaped, 1.6 to 3 millimeters long and 0.4 to 1 millimeters wide. The leaves at the base of the seed cones are 4 to 7 millimeters long, more or less straight and only include the podocarpium. The podocarpium is 4 to 5 millimeters long and turns dark purple when ripe. The seeds are 6 to 8 millimeters long.
  • Dacrycarpus cumingii (Parl.) De Laub. : At least young trees show different types of leaves. The pollen cones are 20 to 30 millimeters long, the microsporophylls are awl-shaped. The leaves at the base of the seed cones are 6 to 13 millimeters long, curved inwards and enclose the podocarpium and part of the seeds.
  • New Zealand warthog ( Dacrycarpus dacrydioides (A. Rich.) De Laub.) : At least young trees show different types of leaves that reach a maximum length of 3 to 7 millimeters. The pollen cones are 8 to 12 millimeters long and 2 to 3 millimeters in diameter. The microsporophylls are pointed. The leaves at the base of the seed cones are 2 to 3 millimeters long, directed outwards and leave the podocarpium largely free. The seeds are 3.5 to 4 millimeters long, smooth and have a notched tip.
  • Dacrycarpus expansus de foliage. : All leaves have the same needle-shaped shape and are sometimes slightly S-shaped, 2 to 6 millimeters long and 0.4 to 1 millimeters wide. The leaves at the base of the seed cones are 4 to 7 millimeters long, more or less straight and only include the podocarpium. The podocarpium is 3 to 4 millimeters long, does not change color when ripe or turns yellowish. The seeds are 5 to 6, sometimes up to 7 millimeters long. The species occurs in central New Guinea.
  • Dacrycarpus imbricatus (flower) de foliage. : At least young trees show different types of leaves that are more or less S-shaped, and older trees from 3 years on are usually 7 to 12 and rarely up to 17 millimeters long and 1 to 2 millimeters wide. Both young and older trees show leaves arranged in two rows. The pollen cones are 8 to 12 millimeters long and 2 to 3 millimeters in diameter. The microsporophylls are pointed. The leaves at the base of the seed cones are 3 to 5 millimeters long, curved inward and at least partially enclose the 4 to 7 millimeter long podocarpium. The seeds are 4 to 7 millimeters long and grooved towards the tip.
  • Dacrycarpus kinabaluensis (Wasscher) de Laub. : At least young trees show different types of leaves. The pollen cones are 8 to 12 millimeters long and 2 to 3 millimeters in diameter. The microsporophylls are pointed. The leaves at the base of the seed cones are 5 to 8 millimeters long, and completely enclose the 3 to 7 millimeters long, blue to purple podocarpium. The species occurs in Borneo in the Gunung Kinabalu.
  • Dacrycarpus steupii (Wasscher) de foliage. : At least young trees show different types of leaves that are more or less S-shaped, 5 to 10 millimeters long and 0.8 to 1.1 millimeters wide. Seedlings and young trees also show leaves arranged in two rows. The pollen cones are 8 to 12 millimeters long and 2 to 3 millimeters in diameter. The microsporophylls are pointed. The leaves at the base of the seed cones are 3 to 5 millimeters long, curved inwards and at least partially enclose the 3 to 4 millimeter long podocarpium. The seeds are 4 to 7 millimeters long and grooved towards the tip. The species is found in the Philippines, Sulawesi, and New Guinea, and used to be found in Borneo.
  • Dacrycarpus vieillardii (Parl.) De foliage. : At least young trees show different types of leaves. The pollen cones are 7 to 10 millimeters long and about 1 millimeter in diameter. The microsporophylls are pointed. The leaves at the base of the seed cones are 1 to 2 millimeters long, and do not enclose the 2 to 3 millimeters long podocarpium. The species occurs in New Caledonia.

use

Two species of the genus, Dacrycarpus imbricatus and Dacrycarpus dacrydioides , are among the largest representatives of the stone slab family and reach similar heights as Sundacarpus amarus and the Rimu resin slice ( Dacrydium cupressinum ) in their range . The species are relatively common and therefore have a certain importance as suppliers of wood, although no distinction is made between the species in the use of wood. The representatives of the genera are rarely cultivated and they are only found in a few botanical gardens.

swell

  • Aljos Farjon: A Handbook of the World's Conifers . tape 1 . Brill, Leiden-Boston 2010, ISBN 978-90-04-17718-5 , pp. 317-318 .
  • James E. Eckenwalder: Conifers of the World. The Complete Reference . Timber Press, Portland, OR / London 2009, ISBN 978-0-88192-974-4 , pp. 232-234 .
  • Wu Zheng-yi, Peter H. Raven (Ed.): Flora of China . Volume 4: Cycadaceae through Fagaceae . Science Press / Missouri Botanical Garden Press, Beijing / St. Louis 1999, ISBN 0-915279-70-3 , pp. 79 (English).

Individual evidence

  1. ↑ a b c d e f g Aljos Farjon: A Handbook of the World's Conifers. Volume 1, p. 317.
  2. ↑ a b c d e James E. Eckenwalder: Conifers of the World , p. 232.
  3. ↑ a b James E. Eckenwalder: Conifers of the World , p. 233.
  4. ↑ James E. Eckenwalder: Conifers of the World , p. 234.
  5. ^ Dacrycarpus in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved June 15, 2014.
  6. ^ Liguo Fu, Nan Li, Robert R. Mill: Dacrycarpus , in Flora of China , Volume 4, p. 79.
  7. ↑ Dacrycarpus. In: The International Plant Name Index. Retrieved June 15, 2014 .
  8. ↑ Dacrycarpus. In: The Plant List. Retrieved June 15, 2014 .
  9. ↑ a b c d Rafaël Govaerts (Ed.): Dacrycarpus. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved April 26, 2019.
  10. ^ Aljos Farjon: A Handbook of the World's Conifers. Volume 1, p. 318.

Web links

Commons : Dacrycarpus  - collection of images, videos and audio files
  • Christopher J. Earle: Dacrycarpus. In: The Gymnosperm Database. www.conifers.org, November 23, 2012, accessed June 15, 2014 .
  • Wart disks at Tropicos.org. Missouri Botanical Garden, St. Louis, accessed June 15, 2014.