Macrozamia pauli-guilielmi

This cycad is a slow-growing, palm-like gymnosperm with a subterranean or partially exposed woody stem and a crown of stiff, pinnate leaves. Like other members of the genus Macrozamia, it is dioecious, producing separate male and female cone-bearing plants, with large cones that release seeds coated in a fleshy sarcotesta attractive to native mammals and birds that assist in dispersal. As a long-lived understorey component of its ecosystem, it contributes to soil stabilisation and provides habitat structure, while its cycad-specialist symbiotic root nodules host nitrogen-fixing cyanobacteria that enrich surrounding soils.

The species occurs in a restricted range in Australia, inhabiting forest environments as well as coastal and supratidal margins, where it typically grows in well-drained, sandy or lateritic soils under an open canopy.

The species is classified as Endangered, with a population trend that is decreasing. Its principal threats are altered fire regimes, including both frequent burning and the suppression of natural fire cycles, which disrupts reproductive cycles and seedling establishment. Expansion of annual and perennial non-timber crop agriculture has further reduced and fragmented available habitat, encroaching on remaining populations.

Conservation attention for Macrozamia species generally includes habitat protection within reserves, monitoring of wild populations, ex situ collections in botanic gardens, and research into fire management regimes that balance ecological needs with cycad persistence. Regulation of collection and trade under CITES Appendix II also applies to the genus.

Given its slow growth, long generation time, and ongoing habitat pressures, the species' outlook remains precarious, with continued population decline expected unless fire management and habitat protection measures are sustained and expanded.