Argophyllum cryptophlebum

Argophyllum cryptophlebum is an evergreen shrub growing up to 7 m (23 ft) tall. The new growth is rusty-brown in colour due to a dense covering of hairs. The leaves are dark green and hairless above and silvery below, and they measure up to 13 cm (5.1 in) long by 6 cm (2.4 in) wide. They are arranged alternately, and held on petioles measuring from 1.3 to 3.8 cm (0.51 to 1.50 in) long. They each have 6 to 9 lateral veins on either side of the midrib, and the leaf blades are broadly elliptic to broadly ovate in shape. The leaf margins (edges) are finely toothed with between 7 and 14 teeth on either edge measuring up to 0.8 mm (0.031 in) long. The inflorescence is produced terminally, is much branched and densely hairy, and measures up to 12 cm (4.7 in) long. Flowers are white with petals about 2.5 mm (0.098 in) long. The fruit is a capsule about 3.5 mm (0.14 in) long and 4 mm (0.16 in) wide.

Phenology. Flowering has been recorded from July to December, and fruit have been observed from March to December.

This species is found in very small areas within the Wet Tropics of northeastern Queensland, north and south of Cairns. It has strict requirements of high rainfall (above 3,000 mm (120 in) p.a.), altitude above 600 m (2,000 ft), and soils derived from granite. Correspondingly it is only found in two localities: the Cape Tribulation area (approximately 95 km (59 mi) north of Cairns, and in the high coastal ranges immediately south of Cairns. In both localities it grows in and on the margins of highland rainforest and alongside creeks. The species' area of occupancy is calculated to be just 88 km2 (34 sq mi).

The genus name Argophyllum is constructed from the Ancient Greek words Ἄργος (argós), meaning bright or shining, and φύλλον (phúllon), meaning leaf. It refers to the shiny undersides of the leaves of the genus. The species epithet cryptophlebum is also from Ancient Greek words, namely κρυπτός (krúptō), meaning hidden, and φλέψ (phléps), meaning vein. It is unclear what Zemann was referring to but it is likely to be the obscure tertiary venation.