A shrub to 2 metres tall (often smaller).
It is confined naturally to the larger Sydney area, growing from the Royal National Park (south of Sydney) north to around the Peats Ridge area and as far west as Hornsby – Parramatta. There is at least one disjunct record down towards Nowra. It is typically found on Hawkesbury Sandstone in dry rocky heathland, shrubland and sclerophyll woodland.
It has branches with rough hairs.
Philotheca spp. have simple and alternate leaves (a trait it shares with its relative, Citrus), often with conspicuous oil glands and odorous.
In this species, leaves are crowded, thinly linear, tubular (terete) to 20 mm long and to 2 mm wide, with prominent glandular protrusions over the entirety, hairy to hairless.
Philotheca spp. produce flowers in leaf axils or at the terminals, often reduced to single flowers with leaves in-between or in cymose or racemose groups. Flowers have 5 sepals (rarely 4) and 5 petals (rarely 4).
In this species, flowers are arranged singly or in 2s or 3s mostly at branch terminals, with petals pink to purple, to 30 mm across, with the stamens densely hairy and joined along their lower half, and with filament hairs reaching the anthers and with anthers also having apical tuft of hairs (useful for identification); occurring mainly in August to December.
The fruit of Philotheca is a schizocarp-capsule – which splits into equal segments on maturity which each segment called a coccus (plural cocci). In this species, the fruit is oblong, to 6 mm long.
Not much is known about the cultivation of this species and it is not widely grown.
It may be difficult to cultivate or may need more application. It may be available for cultivation in the future.
Check with local native nurseries.
Philothecas can be challenging to grow but often with more success than the related Boronias. They are very attractive in flower and well worth the effort.
In a garden situation it grows best in a well-drained soils in full sun. They can succumb quickly to poor drainage. Place in a well-drained sandy soil, in semi-shade to full sun, preferably on a slope. Lightly prune after flowering to maintain compact shape. Flowers attract bees and butterflies.
Very useful in rockeries and sloping gardens.
In common with most members of the Rutaceae, propagation from seed is difficult. Cuttings usually strike readily from current season’s growth but some species can be slow to form roots.
Very similar to P. salsolifolia which occurs over the same area. This editor has learnt from other botanists that the two species can be easily confused.
In this species, the anthers are mostly concealed by the hairs on the upper parts of filaments and, in addition, the anthers have apical tufts of hairs; whereas they are hairless and more visible, sitting above the filament hairs in P. salsolifolia.
The leaves of P. reichenbachii are strongly glandular-punctate (dotted) but much less so in P. salsolifolia.
Philotheca is a genus of about fifty species, all are endemic to Australia with species in every state except the Northern Territory. NSW currently has 20 species.
Many plants formerly in Eriostemon are now in this genus.
See this link: https://en.wikipedia.org/wiki/Philotheca#cite_note-11 for a list of Philotheca species accepted by the Australian Plant Census as at April 2019.
Most Philotheca plants would die in a fire and regenerate from the seedbank.
Philotheca – was first described by Edward Rudge in 1812. As there are some reported variations on the meaning – the Latin of Rudge in his publication was transcribed for these profiles as follows:
all as in Eriostemone, but the habit is very different from that of the ericoid branches; The terminal flowers and the filaments below, enlarged into the naked box, whence the name.
It has been reported that Psilos (ψιλός) refers to “naked” or “bare” in Ancient Greek. Philos (φίλος) in Greek tends to mean “friend”. Philia (φιλία) in Ancient Greek means “highest form of love”
The suffix -theca refers to “box” or “case” in Ancient Greek. Hence, it is thought the name means “naked-box” or “loving-box” referring to the condition of the 10 (or 8) stamens that are fused at the base and forming a box-like structure. (Note: this is not the case in all species with some having free stamens).
reichenbachii – named in Honour of German botanist, Ludwig Reichenbach (1793-1879), who was also an ornithologist and later a director of the natural history museum in Dresden.
This species is not considered to be at risk of extinction in the wild.
Plants of South-Eastern New South Wales – Philotheca reichenbachii profile page.
NSW Flora Online (PlantNET) – Philotheca reichenbachii profile page
Wikipedia – Philotheca reichenbachii profile page