Cycad (Cycas circinalis)
|Also known as:||common pitogo, queen sago|
|Size||Trunk height: to 7 m (2)|
Trunk diameter: 12 – 27 cm (2)
This cycad is classified as Endangered (EN) on the IUCN Red List (1), and listed on Appendix II of CITES (3).
This stout cycad (Cycas circinalis) has a trunk covered in thick and corky bark, which terminates in a crown of long, bright green, slightly glossy leaves. Each leaf, measuring 150 to 170 centimetres long, bears 54 to 110 flat leaflets, arranged opposite each other along the central stem (2). The scientific name circinalis comes from the Latin word for coiled and refers to the way the leaf unfolds as it grows (4). Male Cycas circinalis plants bear yellowish-brown cones, which are egg-shaped to conical and measure between 24 and 48 centimetres long and 12 and 18 centimetres across (2) (4). Like other Cycas species, the female plants do not bear cones; instead they carry ovules and seeds on large, leaf-like sporophylls. These are covered with short, dense orange hairs and measure 20 to 35 centimetres long (2). The seeds of Cycas circinalis are quite small (up to 39 millimetres long) with a light reddish-yellow fleshy covering (2) (4).
There has been much uncertainty over the range of this cycad due to confusion with similar species, but it is now thought that Cycas circinalis is endemic to India, where it occurs in the Western Ghats, in the states of Kerala, Karnataka, Tami Nadu and Maharashtra (5).
Cycas circinalis typically occurs in fairly dense, shrub-woodlands in hilly areas (2) (5). It appears to be a fairly adaptable species and can grow on both rocky hill outcrops and coastal habitats at sea level (2).
Very little is known about the life-history or ecology of this cycad, although it is clear that this species may play an important role within its ecosystem (6). It is host to the plains cupid butterfly (Edales pandava) and ants have been observed collecting secretions found on the cycad’s emerging leaves, as well as collecting secretions from the larvae of the plains cupid butterfly. In addition, it is believed that fruit bats may feed on the seeds of Cycas circinalis, which provides one of the few food sources in the forest during the monsoon season. Finally, epiphytes have been found growing on the cycad’s bark, and spiders weave webs across the leaflets, illustrating the numerous roles this species plays in the forest ecosystem (6).
Like many trees in the shrub-woodlands of the Western Ghats that lose their leaves during the dry season, Cycas circinalis may also shed its leaves at the end of the growing season in extremely dry times (2).
While in many areas Cycas circinalis remains abundant, in others its habitat has been severely reduced and degraded (2). In addition, this cycad is used in numerous ways by the local human population and some of this exploitation is having a negative impact on cycad numbers. Cycas circinalis is heavily harvested for its leaves, with young leaves being used as food and medicine by indigenous and local communities, and the mature leaves being sold in the floriculture industry (7). The biggest impact on C. circinalis populations, however, comes from the harvest of pith and male cone for the medicinal plant industry. While much of this harvest is illegal, it is very difficult to patrol (7). It is not only the cycad itself that this harvesting may threaten; the harvesting of its seeds for human consumption appears to have little negative impact on Cycas circinalis populations, but very heavy seed harvest could have an impact on the bats which reportedly feed on the seeds (7).
Significant populations of Cycas circinalis still exist in a number of national parks and forest reserves (2), which offers this species some protection. To reduce harvesting pressure on populations it has been suggested that people need to be encouraged to use substitutes. For example, the floriculture industry could use leaves from cultivated palms that are faster growing. A substitute for the pith and male cone for the medicinal plant industry is not likely, and thus in these cases, populations need to be increased through cultivation (7).
Efforts have already been made to work with communities within the Niligiri Biosphere Reserve to grow Cycas circinalis in nurseries, and it is hoped that in the future they will be planted in forest areas where their populations are declining (7). However, individuals may take around 50 years to reach harvest size and so, in the meantime, it is vital to protect the remaining populations in order to ensure the long-term survival of this valuable cycad (7).
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- Endemic: a species or taxonomic group that is only found in one particular country or geographic area.
- Epiphytes: plants that use another plant, typically a tree, for their physical support, but which do not draw nourishment from it.
- Larvae: stage in an animal’s lifecycle after it hatches from the egg. Larvae are typically very different in appearance to adults; they are able to feed and move around but usually are unable to reproduce.
- Ovules: structures within the female reproductive organs of plants that contain eggs and when fertilized by pollen, develop into seeds.
- Sporophylls: a sporophyll is a leaf that produces spores, reproductive structures that are adapted for dispersal and surviving for extended periods of time in unfavourable conditions.
IUCN Red List (April, 2011)
- Lindstrom, A.J. and Hill, K.D. (2007) The genus Cycas (Cycadaceae) in India. Telopea, 11(4): 463 - 488.
CITES (June, 2007)
- Whitelock, L.M. (2002) The Cycads. Timber Press, Portland, Oregon.
- Hill, K.D. (1995) The genus Cycas (Cycadaceae) in the Indian Region, with notes on the application and typification of the name Cycas circinalis. Taxon, 44(1): 23 - 31.
- Saneesh, C.S. and Varghese, A. (2007) Mutualistic relationships involving the endemic Cycas circinalis L.: Field notes from the Appankappu Forests, Nilambur, Kerala, India. The Cycad Newsletter, 30(4): 28 - 29.
- Varghese, A. and Ticktin, T. (2006) Harvest, trade, and conservation of the endemic multi-use cycad, Cycas circinalis L., in the Nilgiri Biosphere Reserve, South India. Keystone Foundation, Tamil Nadu, India.