Psidium L.

Myrtaceae, B. Verdcourt, B.Sc., Ph.D.. Flora of Tropical East Africa. 2001

Morphology General Habit

Trees or shrubs

Morphology Leaves

Leaves opposite (at least in ours)

Morphology Reproductive morphology Inflorescences

Inflorescence axillary, 1–3-flowered

Morphology Reproductive morphology Flowers Calyx

Calyx unlobed and almost or completely concealing the corolla before anthesis, subsequently splitting irregularly into 4–5 lobes, persistent

Morphology Reproductive morphology Flowers Corolla

Petals 4–5

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens numerous, free

Morphology Reproductive morphology Flowers Gynoecium Ovary

Ovary imperfectly (2–)4–5(–7)-locular with 4–5 intrusive parietal placentas; ovules numerous

Morphology Reproductive morphology Fruits

Fruit a berry with numerous angular seeds.

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

Distribution

Its native range is from South America to Mexico, but it has become widely naturalised in subtropical and tropical areas of the world, including New Guinea. A genus of about 100 species.

Morphology General Habit

Shrubs and small trees to 9 m tall; bark scaly, young branchlets 4-angled

Morphology Leaves

Leaves elliptic to ovate, apex obtuse, acute or revolute, midrib and lateral veins equally prominent (in New Guinea). Inflorescence solitary, in triads or dichasia

Morphology Reproductive morphology Flowers

Flowers 4–5-merous; calyx lobes partly fused, tearing between the lobes, persistent and erect in fruit; ovary ±inferior

Morphology Reproductive morphology Fruits

Fruit fleshy, obovate to globular, exocarp leathery, yellowish or pink; mesocarp white or pink (in New Guinea)

Morphology Reproductive morphology Seeds

Seeds reniform, embedded in the mesocarp, testa rough and very hard; embryo C-shaped with small cotyledons.

Ecology

Psidium is widely cultivated for the fruits (guava) and may also be naturalised in almost any habitat.

Recognition

The prominent, ladder-like secondary venation, calyx lobes that tear when the flowers open and the rough, hard seeds embedded in the fleshy mesocarp should distinguish Psidium from other Myrtaceae in New Guinea. Psidium guajava L. (guava) and P. cattleyanum Sabine (strawberry guava) are widely cultivated for their fruit and these are the species most likely to be encountered in New Guinea.