The Red-capped Gum (Eucalyptus erythrocorys) is one of the beautiful flowering eucalypts that flowers during summer through to autumn months – seen flowering in January, February, April and September.

Grouped in threes, the flowers that start off green, emerge from rectangular shaped buds with a wart looking vivid red cap (the red caps can be seen strewn on the ground). The yellow flowers can be up to 7 cm across with four tufts of golden stamens at each of the “corners”, giving the flower a squarish look. The seed capsule are large helmet-shaped fruits.

 A mallee shrub or small tree that can grow to 4 metres in height, forming a lignotuber. The bark is rough and creamy under the loose brown bark.

A small tree of subcoastal areas north of Perth, it is a popular street tree in many South Australia and Western Australia country towns.

Common name
Illyarrie, Red-capped Gum, Helmet Nut Gum.

Breaking down the scientific name, did you know the meaning of erythro is red, corys is helmet. When you look at one of the native bee species Megachile erythropyga that can sometimes be seen on Eucalyptus erythrocorys, the erythro is prefix to pyga, which means red rump, meaning this bee has a “red rump”.

Source: many thanks to Gary Taylor for his input into the Latin translation.


  • Scientific classification
  • Kingdom: Plantae
  • Clade: Tracheophytes
  • Clade: Angiosperms
  • Clade: Eudicots
  • Clade: Rosids
  • Order: Myrtales
  • Family: Myrtaceae
  • Genus: Eucalyptus
  • Species: E. erythrocorys
  • Binomial name: Eucalyptus erythrocorys