[6] The nuts are more nutritious than coconuts,[2] and are so popular that villagers in the highlands will move their entire households closer to trees for the harvest season.

[3] It reaches 10–30 metres (33–98 ft) in height, with a grey trunk[2] of 30 centimetres (12 inches) in diameter and supported by prop roots or flying buttress roots up to forty feet (twelve meters) in length and six inches (15 cm) or more in diameter..[6] The trunk has white mottling and is generally smooth with occasional warts or small knobs as well as rings of leaf scars.

[6] The apex of the leaf is attenuate and doubly-pleated, with prickles pointing up at the tip[6] and along the margins and midrib.

[9] The inflorescence on male trees is a densely-branched spadix with a dozen long spikes, each containing many staminate phalanges.

[10] On female trees, the inflorescence is a single ellipsoid or ovoid syncarp, or fruiting head, with off-white bracts.

[1] Though Martelli did not have a complete syncarp, he knew the cluster of fruit must be large, estimating at least 30 cm in diameter.

[1] People also harvest and eat nuts of P. antaresensis, P. brosimos, P. dubius, P. iwen, and P. limbatus, and P. odoratissima[7] The specific epithet "julianettii" honors naturalist Amedeo Giulianetti, who found the original type specimens.

[7] In addition to P. brosimos, 'wild karuka' can also refer to P. antaresensis,[16] P. iwen, and P. limbatus, but nuts from these trees are a much smaller part of the local diet.

[25] According to field research by Kiwo et al. in Melagineri District, Lanny Jaya, the Lani people call it gawin, with woromo for P. brosimos, owandak for P.

[26] Meanwhile according to field research by Zebua et al. in Pirime District, Lanny Jaya, woromo is used to refer to P. Iwen,[27] while in another study in Jayawijaya, the Lani used woromo for P. julianettii with the Dani people call it tuke,[24][25] hence the names have been used interchangeably by multiple publications from different regions and might be a separate species in the complex.

Benjamin Clemens Stone posits that P. julianettii and P. brosimos are a single species with many varieties, but does not support this point.

[6][3] Wild trees are found on the Huon Peninsula and in the highlands of New Guinea's central cordillera.

[7] According to the Kalam people of Madang Province, the Lorentz's mosaic-tailed rat (Paramelomys lorentzii) helps spread karuka seeds.

[14] Bush crickets are serious insect pests, including Segestes gracilis and Segestidea montana, which eat the leaves and can sometimes kill trees.

[3] On New Guinea karuka is cultivated crop,[6] and has been used as a major food source since nearly 31,000 years ago in the Pleistocene.

[13] In PNG nearly 2 million people (almost half the rural population) live in regions where karuka is commonly eaten.

[16] There is high demand for it in the New Guinea Highlands: Entire households (including pigs, who are sometimes fed the fruits[2]) will move from the valleys to higher elevations at harvest time,[7] often for several weeks.

[8] With some coordination between state agencies and private sector, karuka could have export market access.

[16] The crop has a medium potential for large-scale sustainable commercialization in the region, but care must be taken in the sensitive local environments to expanded agriculture.

[6] The uncooked clusters can also be stored for months buried in waterlogged earth,[6][3][2] which possibly ferments it.

[6] The spongy core of the multiple fruit cluster can also be cooked and eaten after the nuts are removed.

[6][3] The high fat content means the nuts can be processed into an edible yellow oil.

[24] Some subjective reports indicate that children are healthier after karuka season, but there may also be increased incidence of tropical ulcers and pig-bel (caused by Clostridium perfringens).

[28] The durable white spathe leaves on male inflorescences are used by the Wola people to wrap pearl shells.

[29] In Upper Karint near Pingirip, karukas are planted as boundary lines between garden plots.

[3] In PNG's Central Province Premier Rugby League the team for Goilala District is called the Karukas.