The Cycads

A relict plant group of the past

presented by the Botanical Garden, Oslo

CONTENTS

Introduction

Systematic position

Description

Distribution

Ethnobotany

Conservation of the Cycads

Acknowledgements

Description

General description

Palm-like plants, pachycaul with tap-root and usually unbranched, dioecious. Leaves large, pinnate. Reproductive organs in cones. Seeds large, microsporophylls scale-like or peltate. Pollen with spiral band of flagella. Cotyledons 2. The Cycads are represented by 3 families:

Cycadaceae: 1 genus with ca. 20 species
Stangeriaceae: 1 genus with only 1 sp.
Zamiaceae: 8 genera with ca. 100 species

based on the vein system in the pinnae.

The families and genera.

1. Cycadaceae

To 15 m palm-like trees with trunk clothed in leaf-bases. Pinnae lanceolate with prominent mid-vein but no laterals. Male sporophylls in cones, females leafy, toothed to deeply lobed with large seeds laterally and terminally. 1 genus:

Cycas

2. Zamiaceae

Palm-like trees to 18 m, or with underground stems. Leaves 1-2 pinnate. The pinnae midrib-less, but with parallel and longitudinal veins. Male and female sporophylls in cones. 8 genera:

Bowenia
Ceratozamia
Dioon
Encephalartos
Lepidozamia
Macrozamia
Microcycas
Zamia

3. Stangeriaceae

Fern-like, with a swollen turnip-like branched stem. Leaves pinnate. The pinnae with prominent mid-vein and lateral veins.. Male and female sporophylls in cones. 1 genus:

Stangeria (S. eriopus)