Parasitaxus

Source: Wikipedia, the free encyclopedia.

Parasitaxus
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Gymnospermae
Division: Pinophyta
Class: Pinopsida
Order:
Araucariales
Family: Podocarpaceae
Genus: Parasitaxus
de Laub.
Species:
P. usta
Binomial name
Parasitaxus usta
(
de Laub.
Synonyms
  • Podocarpus ustus
  • Dacrydium ustum
  • Nageia usta
  • Parasitaxus ustus

Parasitaxus usta, also known in French as cèdre rabougri, is a rare species of conifer of the family Podocarpaceae, and the sole species of the genus Parasitaxus.

Description

It is a woody shrub up to 1.8 m endemic to the remote, densely forested areas of New Caledonia, first discovered and described by Vieillard in 1861. The first definitive report that it was a parasite was in 1959.[2]

Taxonomy

Molecular phylogenetic analysis also suggest affinities between Parasitaxus and the genera Manoao (New Zealand) and Lagarostrobos (Tasmania).[3] Parasitaxus has been shown to contain high levels of chlorophyll.[4] However, a genome analysis shows that many genes for photosynthesis are missing from the parasite's plastid genome,[5] strongly suggesting that Parasitaxus completely depends on its host for survival. Around 60% of the genes normally present in a podocarp plastid genome were entirely absent or present only as fragments. They were predominantly genes involved in photosynthetic, rather than other plastid processes. There were changes to the structure of the plastid genome that were different from that of other parasitic plants and its podocarp relatives, although these might not be related to its parasitic lifestyle.

Glaucous white seed cones.

Usta means 'parched'.

Brongn. & Gris, and Nageia usta (Vieill.) Kuntze
. The name is often cited as Parasitaxus ustus, but this is grammatically incorrect, as, according to Latin, the genus name Parasitaxus is (like Taxus) gender-feminine, with which the species name's gender must agree (Nickrent 2006). The scientific name translates as "parched parasitic yew."

Ecology

It is generally mentioned that Parasitaxus usta is the only known

angiosperms. Certain experts therefore consider the plant as a myco-heterotroph.[4]

References

  1. doi:10.2305/IUCN.UK.2010-3.RLTS.T31002A9597883.en
    . Retrieved 12 December 2017.
  2. ^
    doi:10.1126/science.130.3367.97.a
    .
  3. ^ Sinclair, W. T., R. R. Mill, M. F. Gardner, P. Woltz, T. Jaffré, J. Preston, M. L. Hollingsworth, A. Ponge, and M. Möller. (2002) Evolutionary Relationships of the New Caledonian Heterotrophic Conifer Parasitaxus Ustus (Podocarpaceae), Inferred from Chloroplast trnL-F Intron/Spacer and Nuclear ITS2 Sequences. Plant Systematics and Evolution 233: 79–104.
  4. ^
    doi:10.1111/j.1365-3040.2005.01378.x
    .
  5. PMID 31504501
    .
  6. ISBN 9780521685535
    (paperback). pp 395
Retrieved from "https://en.wikipedia.org/w/index.php?title=Parasitaxus&oldid=1185176172"