The life-form of the mature plant is classified according to the system of Raunkiaer (1934), as modified by Govaerts et al. (2000). Broadly speaking, the approach classifies plants according to the positions of their perennating buds (hence the level of protection that buds are given), during seasons that are unfavourable for growth. A summary of the classification is provided below, and abbreviations used in SID are given in parentheses.
- Phanerophytes (phan.) have stems that are woody and persistent, and buds that are normally exposed 3 m or more above ground level. This category includes trees and large shrubs
- Nanophanerophytes (nanophan.) also have woody, persistent stems, but are lower in stature with buds typically located between 0.5 m and 3 m above ground level. This category includes smaller shrubs.
- Herbaceous phanerophytes (herb. phan.) have herbaceous stems that persist for several years and include tropical species such as bananas and plantains.
- Chamaephytes (cham.) can have stems that are herbaceous or woody and persistent, and have buds that are located above soil level, but never by more than 50 cm. This group includes dwarf shrubs and some perennial herbs.
- Hemicryptophytes (hemicr.) have herbaceous stems that often die-back during unfavourable seasons, and surviving buds placed on (or just below) soil level. This group includes many biennial and perennial herbs, including those in which buds grow from a basal rosette.
- Geophytes (not abbreviated) have stems that die back during unfavourable seasons, with the plant surviving as a bulb, rhizome, tuber or root bud.
- Therophytes (ther.) complete their entire life-cycle during the favourable season, and survive the unfavourable season as a seed. This group includes all annual herbs.
- Epiphytes (epi.) grow on other plants (their growing buds occur on another plant).
- Helophytes (hel.) are plants in which surviving buds are buried in water-saturated soil, or below water-level, but that have flowers and leaves that are fully emergent during the growing season. The group includes many marsh and emergent aquatic herbs.
- Hydrophytes (hydro.) are fully aquatic herbs in which surviving buds are submerged, or buried in soil beneath water. Their stems and vegetative shoots grow entirely underwater and leaves can be submerged or floating, but only the flower-bearing parts may be emergent.
The above categories may be preceded by the following terms:
- cl. denotes a climbing plant.
- succ. denotes a plant having succulent stems.
- par. denotes a plant that is parasitic.
Govaerts, R., Frodin, D.G. and Radcliffe-Smith, A. 2000. World Checklist and Bibliography of Euphorbiaceae (with Pandanaceae). Volume 1. The Royal Botanic Gardens, Kew.
Raunkiaer, C. 1934. The Life Forms of Plants and Statistical Plant Geography. The Clarendon Press, Oxford.