Philotheca is a genus of about fifty species of flowering plants in the family Rutaceae. Plants in this genus are shrubs with simple leaves arranged alternately along the stems, flowers that usually have five sepals, five petals and ten stamens that curve inwards over the ovary. All species are endemic to Australia and there are species in every state, but not the Northern Territory.

Description

Plants in the genus Philotheca are shrubs that are either glabrous or have tiny, simple hairs. The leaves are arranged alternately along the stems, narrow oblong to almost cylindrical and sessile or on a very short petiole. From a single to many flowers are arranged in leaf axils or on the ends of the branchlets. The flowers have five sepals and five petals (except in P. virgata which has four). The sepals are free from each other and the petals usually overlap at their bases. There are ten stamens that curve inwards over the ovary with anthers that have an appendage called the "apiculum". The ovary contains five carpels fused near their bases. The seeds are 2-5 mm long and are released explosively from their capsule.

Taxonomy and naming

The genus Philotheca was first formally described in 1816 by Edward Rudge from a specimen collected near Port Jackson and the description was published in Transactions of the Linnean Society of London. The first species Rudge described was P. australis but this name is considered a nomen illegitimum and a taxonomic synonym of Philotheca salsolifolia by the Australian Plant Census. The name Philotheca should have been written Psilotheca after the Ancient Greek words psilos meaning "bare", "smooth", "bald" or "naked" and theke meaning "case", "container", "envelope" or "sheath", referring to "the smooth tube of the stamens". Many plants formerly in Eriostemon are now in this genus.

Distribution

Plants in the genus Philotheca are found in every state of Australia, but not in the Northern Territory.

Species

The following is a list of Philotheca species accepted by the Australian Plant Census as at April 2019: