- Category: Plants
Cycas is generally recognised as the most distinct of all living genera of cycads and its reproductive organs are considered by some authorities to be the most primitive in this very ancient group of plants.
Cycas is the most widely ranging cycad genus and its species occur naturally from the southern tip of Japan through the Malay Archipelago, Guam and the mainland of South-east Asia as far as Central China, west through parts of southern western India and Sri Lanka, and as far as Madagascar and the eastern African coast. The range also extends south through the Philippines and Indonesia and eastward of new Guinea, Solomon Islands and the northern half of Australia.
All members of the genus have an above-ground stem, usually but not always forming a trunk which in older specimens of some species (e.g. C. angulata) may reach a height of 8 - 10 metres and in older specimens of other species (e.g. C. circinalis, C. revoluta) is often branched. The outward appearance of the trunk is very similar to that of many other trunking cycads,
In other ways, Cycas is the most structurally and genetically distinct genus in the Cycadales. The leaves and stems have certain peculiarities, but the most characteristic and unique feature is the apparently primitive nature of the reproductive organs. Unlike their counterparts in other genera, the megasporophylls of Cycas do not form a determinate female cone, although they are somewhat tightly clustered together when first emerging. After pollination, the megasporophylls of certain species relax and spread out like leaves, then hang down, and eventually, after the seeds ripen and are shed, and fall off the plant individually.
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