Hypericum aegypticum is a species of flowering plant of the St. John's wort family (Hypericaceae) which is native to the Eastern Mediterranean.

The species is a shrub or shrublet that grows up to 2 meters (6.5 feet) tall with many branches, each having a single small flower with five yellow petals and many stamens.

The species is notable for its heterostyly, a trait which within the Hypericum genus is unique to section Adenotrias, and exhibits one of two heterostylous flower types called "pins" and "thrums".

Hypericum aegypticum is a shrub or shrublet that varies in height from 0.05 to 2 meters (0.16 to 6.5 feet) tall.

[3] The xylem in the stems, a type of transport tissue, differs from other similar species of Hypericum.

[3] Unlike some species of Hypericum, such as H. perforatum, H. aegypticum lacks black nodules on its leaves.

[6] The upper sides of the leaves have an outer layer (epidermis) made of cells with linear walls and rounded corners.

On both sides, there is a cuticle that extends over the entire surface, even over the guard cells, which makes them very hard to distinguish.

The sepals are hood-like and stand stiffly erect, and have roughly nine unbranched veins with prominent midribs and linear laminar glands.

The seeds are dark brown and roughly 1.5 millimeters (0.06 inches) long and lack a longitudinal ridge.

[3] Individual plants of Hypericum aegypticum exhibit one of two different sets of characteristics, called distyly.

This trait is thought to have evolved within the genus as opposed to being primitive and is one of the unique characteristics of sect.

[9]: 272 The phytochemistry of Hypericum aegypticum varies a great deal depending on which subspecies is analyzed.

[11]: 305  Small amounts of other metabolites are also present in H. aegypticum, including flavonoids (3.95 g/kg), biflavones (1.45 g/kg), acylphloroglucinols (1.15 g/kg), cinnamic acids (0.35 g/kg), and naphtodianthrones (0.05 g/kg).

webbii were shown in vitro to have moderate antimicrobial effects against Gram-positive bacteria such as Bacillus subtilis, Enterococcus faecalis, Staphylococcus epidermidis, and Micrococcus luteus.

[12]: 427 Hypericum aegypticum can be found frequently in the wild and is indigenous to Malta, Greece, Morocco, Algeria, and Libya.

[14] In some habitats, particularly more wind-swept or exposed areas, the species has been observed in much denser, carpet-like growth patterns, sometimes growing to only 20–30 centimetres (8–12 in) tall.

[15] While H. aegypticum has been identified by the Maltese Red Data Book as having a threatened status on Malta, no legal action has been taken for the protection of the species as of 2021.

In the early 19th century, the species of Hypericum were being divided into numerous smaller, new genera by different authors.

Antoine Laurent de Jussieu split it into five genera, confusingly including one called Elodea.

[4]: 306 In 1996, British taxonomist Norman Robson published the sixth volume of his comprehensive monograph on the genus Hypericum.

[20]: 3–4  In this volume, Robson recognized Linnaeus' original name as correct and maintained H. aegypticum in sect.

[3] Adenotrias was established to comprise three species of shrubs found among limestone rocks which vary greatly in appearance.

[15] Molecular phylogenetics has demonstrated that Hypericum aegypticum is most closely related to H. balfourii and H. socotranum of sect.

However, no conclusive evidence was found which would suggest that these similarities would warrant the inclusion of H. aegypticum in sect.

This suggests that H. heterophyllum is a derivative of the species which has lost some of the specializations that are unique to H. aegypticum and sect.

Additionally, the branches of maroccanum tend to reach upwards, while aegypticum usually forms a lower bush.