Cyathea brownii

Synonym: Sphaeropteris excelsa

Other links:

Common name: Norfolk tree fern

Conservation status:

It is available in cultivation in many countries and though rare is not considered endangered

Etymology:

Spores:

Leaves:

Can reach 20 m or more in height
The broad, lance shaped, bipinnate-pinnatifid to tripinnate fronds can reach 5 m in length
Stipe is long and has a line of white, stitch like dashes along its length
Rachis and stipe are covered in white-brown and darker orange-brown scales
The trunk can become smooth with age and may display oval scars left from fallen fronds

Stem & branches:

Roots:

Habit:

Habitat:

Subtropical rainforests
Average daytime temperatures reach around 23 °C during the summer months falling to around 17 °C during the winter
The highest temperatures likely to be experienced in this environment are around 29 °, the lowest around 6 °C.
Relative humidity is fairly consistent at levels of 70 to 80% throughout the year
Yearly rainfall is approximately 1,200 mm

Distribution:

Additional notes:

Sphaeropteris excelsa, synonym Cyathea brownii, commonly known as the Norfolk tree fern or smooth tree fern, is probably the largest fern species in the world. It is endemic to Norfolk Island, in the Pacific Ocean near Australia and New Zealand. It is named after the botanist Robert Brown (1773-1858).

Conservation
- The once extensive forests of Norfolk Island are now reduced to a single small forested area which has been designated part of a national park
- It is protected within this park
Cultivation
- It is cultivated as an ornamental tree
- It requires a neutral to slightly acidic soil rich in organic matter
- The soil must be moisture retentive but well drained
- The tree fern will suffer if left to stand in waterlogged soil
- It requires high humidity and either high rainfall or frequent watering. During the summer months even a very young pot grown plant can consume 0.5 litres of water per day
- Itrequires good light but does best when shaded during the hottest parts of the day. It responds well to fertilization but can be intolerant of some commercial fertilizers producing malformed fronds and a larger but weaker plant. It is able to withstand only light frosts. Larger plants may survive overnight temperatures as low as minus three degrees Celsius.
- In countries such as Britain it is best grown in a conservatory. Its large size however often makes this impractical. A beautiful and rewarding plant but in colder regions it is strictly for the more dedicated of enthusiasts.
- It is easily grown from spore and can be very fast growing when young.