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Cycas siamensis


Cycas siamensis

Family Name: Cycadaceae
Common Name: Siamese Cycad


Family Name
Genus Epithet
Species Epithet
Name Status (botanical)
Common Names

Classifications and Characteristics

Plant Division Gymnosperms (Non-Flowering Seed Plants)
Plant Growth Form Cycad


Native Distribution Central Thailand, Laos and Vietnam
Native Habitat Terrestrial
Preferred Climate Zone Tropical, Sub-Tropical / Monsoonal
Local Conservation Status Non-native

Description and Ethnobotany

Growth Form It is a small cycad with underground or above ground trunk, up to 1.5 m tall, with a swollen base.
Foliage Mature leaves are bright green, feather-like, erect (0.6 – 1.2 m long) and arching, with leaf tips often recurved. Each leaf comprises of 140 – 280 leaflets which are hairy, shiny green above and pale green underneath. Colour of leaflets hairs is variable and range from white, yellow, orange or brown. Petiole is 10 – 30 cm long, hairy and the margin is lined with thorns. Cataphyll is 5 – 7 cm long and densely covered with brown woolly hairs.
Reproductive Parts - non-flowering plant Male cone is narrowly oblong (10 – 24 cm long and 5 – 7.5 cm wide), with orange to brown hairs, and emits a strong unpleasant odour. Female cone is flattened globose (8 – 14 cm diameter), sporophylls are covered with brown hairs and round apical lobes are lined with 22 – 46 spines at the margin. Seed is almost round (3 – 3.7 cm long and 2.5 – 3.5 cm wide) with yellow seed coat.
Habitat It is found in lowland seasonally dry forest with distinct wet and dry season.
Cultivation Established plants are tolerant to drought but sensitive to disturbance, making transplanting difficult. Overwatering during dormant period may result in rot.

Landscaping Features

Plant & Rootzone Preference - Tolerance Well-Drained Soils
Landscape Uses Parks & Gardens

Plant Care and Propagation

Light Preference Full Sun
Water Preference Moderate Water
Plant Growth Rate Slow


Mature Foliage Colour(s) Green


References Jones, D.L. 2002. Cycads of the World. Ancient Plants in Today's Landscape. 2nd Edition. United States of America: Smithsonian Institution Press. 456

Image Repository



Master ID 1287
Species ID 2580
Flora Disclaimer The information in this website has been compiled from reliable sources, such as reference works on medicinal plants. It is not a substitute for medical advice or treatment and NParks does not purport to provide any medical advice. Readers should always consult his/her physician before using or consuming a plant for medicinal purposes.
Species record last updated on: 10 December 2021.