Movatterモバイル変換


[0]ホーム

URL:


The Gymnosperm Database

map

Range of the genusDacrydium (de Laubenfels 1988).

 

Valid HTML 4.01 Transitional

Dacrydium

Sol. ex G.Forst. 1786

Common names

There are no common names for the genus. The species each have distinct names.

Taxonomic notes

A genus of 21 species and one nothospecies:

Type species:Dacrydium cupressinum Sol. ex G.Forst.

Quinn's 1982 revision of the genus concludes that "[a]s here emended, the genusDacrydium is a highly uniform and natural taxon comprising 16 species (de Laubenfels 1969) ... Its closest affinity is withFalcatifolium, as evidenced by the presence of resin ducts and hypodermis in the adult leaves, axial parenchyma and taxodioid cross-field pits in the secondary xylem, and 10 metacentric chromosomes in all members of both genera examined." Moreover:

"Within the Podocarpaceae, genera have largely been recognized on character-states drawn from the morphology of the female cone... [Acmopyle, Saxegothea, Microcachrys, Microstrobos andPhyllocladus] are all relatively small genera in which many other characters of vegetative and reproductive morphology and anatomy have been found to be correlated with the differences in cone morphology, and so go to make up good sets of generic characters of more or less equal content.

"AlthoughPodocarpus s.l. may have been a natural taxon, ... revision byde Laubenfels (1969) divided it into four genera, viz. [Dacrycarpus, Decussocarpus, Prumnopitys andPodocarpus], whose taxonomic content is more nearly equivalent to the preceding genera and to each other" (Quinn 1982).

Quinn (1982) applies similar reasoning to the large and heterogeneous genusDacrydium s.l., accepting Florin's (1931) division of the genus into Sections A, B and C andde Laubenfels' (1969) segregation of Section A asFalcatifolium, retaining Section B asDacrydium sensu strictu and segregating Section C intoLepidothamnus, Lagarostrobos andHalocarpus.

Description

"Trees or shrubs with spreading linear to subulate, sometimes falcate, juvenile leaves that normally give way to shorter, strongly keeled adult leaves in the form of either subulate decurrent needles often with incurved tips, or appressed scales. Plants dioecious; males cones solitary, sessile and terminal or axillary; female cones terminal, consisting of several leaf-like bracts of which only one is usually fertile. Fertile bracts bearing a single ovule in a medial position on the adaxial surface and inclined so that it is partially inverted when first formed. Seed maturing in one season, often slightly flattened and usually remaining distinctly inclined towards the cone axis. At maturity the epimatium forming a submembranous asymmetrical sheath around the base of the seed and less than one-third its height. Cone bracts sometimes becoming fleshy and brightly colored at maturity" (Quinn 1982).

Distribution and Ecology

"[E]xtending from New Zealand in the south through the islands of New Caledonia, Fiji, The Solomons, New Guinea and Indonesia to the Philippines, Thailand and southern China in the north" (Quinn 1982).

Remarkable Specimens

I have found age data for one species,Dacrydium cupressinum, of New Zealand. There is a reliable age of 815 years for an extant specimen, and a vague report of 1200 years (a suspiciously round number) based on ring counts on basal stem sections.

Ethnobotany

"Wood yellow or reddish in colour, sometimes handsomely figured, usually very resinous and durable. It is used for building purposes, furniture and other work" (Dallimoreet al. 1967).

Observations

See the species accounts.

Remarks

Dacrydium is derived from the Greek word for a tear.Dallimoreet al. (1967) andFarjon (2010) both say that this refers to resinous exudations from the wood, butKirk (1889) says it refers to the weeping habit of the trees. The type description by Forster (1786) alludes to this as a cypress, a group of trees that commonly have weeping foliage, so I am partial to Kirk's explanation. As it is relevant, and entertaining in its own right, I here give the type description from Forster (1786), along with its English translation, as an example of what passed for a proper botanical description in the 18th century:

Pulcherrimum hocce Taxoque affine genus, cuius florescentiam non vidimus, ab Illustri Solandro nomen Dacrydii accepit. Reperitur in Nova Zeelandia, vbi Cookius, e junioribus ramusculis, foliis tenellis onustis, et resinosa materia amaricante featentibus, potum, cerevisiae quodammodo similem, parari jubebat, cuius praestantiam in malo scorbutico disertis verbis extollit in hodoeporico & succedaneum potumcereuisiae e taleis Pini canadensis consecti, inque America septentrionali & inter nautas notissimi, vulgo Spruce-beer esse voluit. Non tamen negandum est, hunc e Dacrydio cupressino paratum potum, jejunis nauseam et vertiginem nduxisse, parvo temporis spatio interjecto transeuntem.This is a very beautiful genus, related toTaxus, whose flowers we have not seen. It received the name ofDacrydium from the illustrious Solander. It is found in New Zealand, where Cook ordered the preparation of young twigs, laden with tender leaves, and a resinous substance that gave a bitter odor, a drink somewhat similar to beer, the excellence of which he emphasized in eloquent words, in the case of scurvy. In North America, most famous among sailors, it was commonly known as "spruce-beer". It must not be denied, however, that this drink, prepared from theDacrydium cypress, induced nausea and vertigo in the fasting person, which passed after a short time.

Citations

Florin, R. 1931. Untersuchungen zur Stammesgeschichte der Coniferales und Cordaitales. I. Morphologie und Epidermisstruktur der Assimilationsorgane bei den rezenten Koniferen.K. Svens. Vetenskapskad. Handl. 10(1).

Forster, G. 1786.De Plantis Esculentis Insularum Oceani Australis Commentatio Botanica, p. 80. Available:Biodiversity Heritage Library, accessed 2021.12.24.

See also

Van Royen 1979 provides extensive taxonomic citations.

Back|Home|Contact us

Copyright 2024 The Gymnosperm Database

Edited by Christopher J. Earle

Back to top

Last Modified 2023-03-01


[8]ページ先頭

©2009-2025 Movatter.jp