Phymatocarpus F.Muell.

Scientific Description

Family Myrtaceae.

Habit and leaf form. Shrubs; evergreen; bearing essential oils. Plants with neither basal nor terminal concentrations of leaves; to 1–3 m high. Leptocaul. Helophytic to xerophytic. Leaves minute to small; alternate, or opposite; ‘herbaceous’, or leathery; petiolate; gland-dotted; aromatic; edgewise to the stem, or with ‘normal’ orientation; simple; epulvinate. Leaf blades dorsiventral, or isobilateral, or centric; entire; flat; linear, or lanceolate, or oblong, or ovate; ovate, or oblong, or orbicular; pinnately veined, or parallel-veined, or one-veined; cross-venulate, or without cross-venules. Leaves without stipules; without a persistent basal meristem. Stem anatomy. Secondary thickening developing from a conventional cambial ring.

Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite. Entomophilous, or ornithophilous. Pollination mechanism unspecialized.

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; in heads. Inflorescences simple, or compound. The terminal inflorescence unit cymose. Inflorescences terminal; globular; pseudanthial. Flowers (bi) bracteolate, or ebracteolate; small; regular; 5 merous; cyclic. Free hypanthium present (petals ‘inserted on the calyx’); nearly globose to campanulate. Perianth with distinct calyx and corolla; 10; 2 -whorled; isomerous. Calyx present; 5; 1 -whorled; polysepalous, or gamosepalous (depending on interpretation); imbricate, or valvate; regular; persistent. Sepals ovate to triangular. Corolla present; 5; 1 -whorled; polypetalous; imbricate; regular. Androecial members indefinite in number. Androecium 15, or 40–75. Androecial members branched. Androecial sequence determinable, or not determinable. Androecial members if ‘many’, maturing centripetally; free of the perianth; all equal; free of one another to coherent (in clusters of 3, in P. maxwellii), or coherent (basally, in clusters of 8–15, in P. porphyrocephalus); when united, 5 - adelphous, or 8–15 - adelphous. The androecial groups opposite the petals. Stamens 15, or 40–75; attached on the rim of the hypanthium; becoming exserted (exceeding petals); all more or less similar in shape; triplostemonous to polystemonous; erect in bud, or inflexed in bud. Filaments filiform. Anthers all alike; basifixed; non-versatile; dehiscing transversely; opening outwards; cells back to back; tetrasporangiate. Gynoecium 3 carpelled. The pistil 3 celled. Gynoecium syncarpous; eu-syncarpous; inferior. Ovary plurilocular; 3 locular. Ovary summit hairy, the hairs not confined to radiating bands. Epigynous disk present. Gynoecium stylate. Styles 1; simple; from a depression at the top of the ovary; apical; becoming exserted. Stigmas 1; small. Placentation basal. Ovules 2–4 per locule; ascending (on almost peltate placentae); non-arillate; anatropous.

Fruit and seed features. Fruit non-fleshy; dehiscent; a capsule (3-valved). Capsules loculicidal. Fruit 3 celled; few-seeded. Seeds non-endospermic; winged, or wingless. Cotyledons 2; plano-convex, longer than the radicle. Embryo straight.

Geography, cytology, number of species. Native of Australia. Endemic to Australia. Australian states and territories: Western Australia. South-West Botanical Province.

Etymology. From the Greek phyma -atos (tumour, boil) and carpos (fruit); the fruiting calyx is covered with warts.