Grewia L.

First published in Sp. Pl.: 964 (1753)
This genus is accepted
The native range of this genus is Tropical & Subtropical Old World to Pacific.

Descriptions

Tiliaceae, H. Wild. Flora Zambesiaca 2:1. 1963

Morphology General Habit
Shrubs or smallish trees.
Morphology Leaves
Leaves alternate, simple, serrate or very rarely entire, 3–7-nerved at the base, petiolate; stipules lateral.
Morphology Reproductive morphology Flowers
Flowers in terminal or axillary panicles or in leaf-opposed or axillary umbel-like cymes.
Morphology Reproductive morphology Flowers Calyx
Sepals 5, linear-oblong or linear-spathulate, stellately hairy outside, often coloured within like the petals.
Morphology Reproductive morphology Flowers Corolla
Petals 5, shorter than the sepals, yellow, purplish-blue or white, usually with a nectariferous claw or gland at the base.
Morphology Reproductive morphology Flowers Androecium Stamens
Stamens indefinite, free, usually raised on a torus or androgynophore which is short and glabrous or produced above into a pubescent extension.
Morphology Reproductive morphology Flowers Gynoecium Pistil
Ovary 2–4-locular, entire or 2–4-lobed, with 2 to many axile ovules in each loculus; style longer than the ovary, with subulate or flattened lobes or almost entire.
Morphology Reproductive morphology Fruits
Fruit a 1–4-lobed drupe or berry with 1–4 pyrenes; mesocarp somewhat fleshy or fibrous; endocarp hard and woody.
[FZ]

Tiliaceae, C. Whitehouse, M. Cheek, S. Andrews & B. Verdcourt. Flora of Tropical East Africa. 2001

Morphology General Habit
Small trees or shrubs, often scandent
Morphology Leaves
Leaves alternate, simple, 3–5-nerved from the base, margins serrate to ± entire, petiolate; stipules entire or divided, caducous or sometimes persistent
Morphology Reproductive morphology Inflorescences
Inflorescences axillary, leaf-opposed axillary or terminal cymes, or many-flowered panicles in sect. Microcos
Morphology Reproductive morphology Inflorescences Bracts
Bracts 3 at base of pedicels, small, ovate to linear, caducous, often falling while still in bud, rarely persistent
Morphology Reproductive morphology Flowers
Flowers white, yellow or pink to purple, bisexual or possibly rarely unisexual, (4–)5-merous
Morphology Reproductive morphology Flowers Calyx
Sepals linear-lanceolate to oblong or slightly spathulate, stellate-pubescent outside, usually the same colour as the petals inside
Morphology Reproductive morphology Flowers Corolla
Petals shorter than the sepals, oblong to subcircular, with a nectariferous claw at the base
Morphology Reproductive morphology Flowers Androecium Stamens
Stamens numerous, attached to the hairy node of the androgynophore
Morphology Reproductive morphology Flowers Gynoecium Pistil
Ovary 2–4-locular, entire or 2–4-lobed, with 2–many axile ovules; style similar in length to the stamens; stigma with subulate or flattened lobes (or unlobed in sect. Microcos )
Morphology Reproductive morphology Fruits
Fruit a 1–4-lobed drupe with 1–4 pyrenes; mesocarp somewhat fleshy or fibrous; endocarp hard and woody
Figures
Fig. 3.
[FTEA]

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

Distribution
A genus from warm temperate to tropical habitats from Africa and Asia to Australia and the Pacific. Estimates of the number of species range from 90–300; 11 species in New Guinea.
Morphology General Habit
Trees and shrubs, rarely climbers. Indumentum stellate when present
Morphology Leaves Stipules
Stipules present, entire or divided, caducous
Morphology Leaves
Leaves alternate, elliptic to ovate, margin usually serrate to serrulate, rarely entire, 3-nerved from the base
Morphology Reproductive morphology Inflorescences
Inflorescences axillary, usually 1–3-flowered cymes, sometimes fascicles of triads
Morphology Reproductive morphology Flowers
Flowers usually bisexual, rarely plants dioecious, actinomorphic, (4–)5-merous, often yellow; sepals free, same colour as petals on inner surface, often pubescent on outer surface; petals shorter than the sepals (usually about ½ as long), thickened and densely hairy at base; annular floral disk present, persistent in fruit; stamens numerous, free; ovary superior, 2–4-locular, 2–12(–40) ovules per locule, style simple, stigma minute
Morphology Reproductive morphology Fruits
Fruit drupaceous, often lobed, with 1–4 pyrenes, each pyrene usually 1-seeded
Morphology Reproductive morphology Seeds
Seeds glabrous, sometimes with grooves or ridges.
Ecology
In New Guinea, Grewia occurs in a range of habitats from coastal and lowland rain forest to subarid savannahs between 0–1000 m.
Recognition
Grewia can be distinguished by the leaves which are usually about 1.5 times as long as wide, in contrast to the more oblong leaves of the other Grewioideae genera in New Guinea which are at least twice as long as wide; the few-flowered, axillary inflorescences (usually only 1–3 flowers per axis) and the lobed fruit. The monospecific and rarely collected genus Eleutherostylis also has few-flowered inflorescences, but it often has minute auricles at the base of the lamina which are not present in Grewia (which is rounded or cordate at the base), persistent, asymmetrically shaped stipules (not present in Grewia) and an acuminate leaf tip (acute in Grewia).
[TONG]

Sources

  • Flora Zambesiaca

    • Flora Zambesiaca
    • http://creativecommons.org/licenses/by-nc-sa/3.0
  • Flora of Tropical East Africa

    • Flora of Tropical East Africa
    • http://creativecommons.org/licenses/by-nc-sa/3.0
  • Herbarium Catalogue Specimens

    • 'The Herbarium Catalogue, Royal Botanic Gardens, Kew. Published on the Internet http://www.kew.org/herbcat [accessed on Day Month Year]'. Please enter the date on which you consulted the system.
  • 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
  • Kew Science Photographs

    • Copyright applied to individual images
  • Plants and People Africa

    • Common Names from Plants and People Africa http://www.plantsandpeopleafrica.com/
    • © Plants and People Africa http://www.plantsandpeopleafrica.com http://creativecommons.org/licenses/by/3.0/
  • Trees of New Guinea

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