Astronia Blume

First published in Bijdr. Fl. Ned. Ind.: 1080 (1826)
This genus is accepted
The native range of this genus is Indo-China to Taiwan and Papuasia.

Descriptions

Timothy M. A. Utteridge and Laura V. S. Jennings (2022). Trees of New Guinea. Kew Publishing. Royal Botanic Gardens, Kew

Distribution
A genus of about 60 species distributed from Myanmar through the Malesian region to New Guinea. About 30 species are recorded from New Guinea.
Morphology General Habit
Trees to 25 m tall
Morphology Branches
Branchlets compressed to quadrangular
Morphology General Indumentum
Indumentum red-brown, scaly, densely covering branchlets, inflorescence axis and veins of leaf underside, becoming glabrous with age. Leaves opposite, petiolate, entire, subcoriaceous, opposite pairs equal in size, lanceolate, ovate or oblong, base narrowing into the petiole, margins entire or crenate, often slightly recurved, 3(–5)-nerved from the base, cross venation visible
Morphology Reproductive morphology Inflorescences
Inflorescences terminal or in the uppermost axils, many-flowered, cymose or paniculate
Morphology Reproductive morphology Flowers
Flowers staminate or bisexual and plants androdioecious, usually 5-merous; calyx tube with 5 triangular lobes, extending above the ovary summit; petals membranous, white or brown; anthers wedge-shaped, isomorphous, dehiscing by slits; ovary 2–5-locular, extra-ovarian chambers and septa absent, placentas basal, usually 2; stigma capitate in bisexual flowers
Morphology Reproductive morphology Fruits
Fruit a globose capsule, dehiscing irregularly, the vascular bundles of the hypanthium persisting as a dome-shaped frame
Morphology Reproductive morphology Seeds
Seeds numerous.
Ecology
Astronia has been recorded from rain forest, montane forest, and secondary regrowth and is often associated with Nothofagus, and has been collected in New Guinea between sea level and 2900 m, but most commonly above 500 m.
Recognition
The genera Astronia and Astronidium are often difficult to tell apart from herbarium material: both genera have leaves with entire margins and visible cross venation; usually with a short, reddish-brown, scaly indumentum on the branchlets, inflorescences and the veins of the leaf underside, while the upper side of the leaf is glabrous; terminal, paniculate inflorescences; and anthers dehiscing by slits. In addition, the distinctive way that the fruit shatters in both genera, leaving behind a skeletal ‘dome’ of vasculature – this is not known elsewhere in the family. Astronia can be distinguished from Astronidium by the staminate and bisexual flowers on the androdioecious plants (bisexual flowers only in Astronidium), anthers without spurs (spurred in Astronidium), 2 basal cushion-like placentae (usually at least 4 and erect in Astronidium) and capitate stigma (not capitate in Astronidium).
[TONG]

Sources

  • Herbarium Catalogue Specimens

  • Kew Backbone Distributions

    • The International Plant Names Index and World Checklist of Vascular Plants 2024. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2023 World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0
  • Kew Names and Taxonomic Backbone

    • The International Plant Names Index and World Checklist of Vascular Plants 2024. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2023 International Plant Names Index and World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0
  • Trees of New Guinea

    • Trees of New Guinea
    • http://creativecommons.org/licenses/by-nc-sa/3.0