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Scientific name: Cycas Found in the Jurassic period of the Mesozoic era. (250-145 million years ago) They can grow in Subtropical and Tropical climates. They grow in any type of soil; mostly moist habitats. 185 different species of Cycads Gymnosperms naked seed Four major living groups. Cycads (Cycadophyta), Welwitschia group (Gnetophyta), Ginkgo, the Maiden Hair Tree (Ginkgophyta), and the conifers (Pinophyta) . Cycas bougainvilleana Cycads Cycads resemble palms or tree-ferns in overall appearance but differ greatly in detailed structure and reproductive behaviour. Cycads are dioecious (i.e. male and female reproductive structures are borne on separate plants), and reproduction is by seeds produced on open carpophylls or seedbearing leaves. Although technically woody plants, unlike other woody plants, cycads have a thick, soft stem or trunk made up of mostly storage tissue with very little true wood. The living cycads include about 250 species, with 11 genera in 3 families. Microcycas calocoma Photo Dennis Stevenson Female coneCuban species Cycas-Circinate vernation of young foliage leaf Cycas-Coralloid root T.S. Leaflet of Cycas Cycas- T.S. Microsporophyll Cycas- Young ovule Cycas- Megasporophyll with young ovule Cycas- Mature ovule Cycas- Mature ovule The microspores develop into pollen grains. This female gametophyte is developed from the megaspores. *the dominant lifecycle stage is the sporophyte. Sporophyte relies on gametophyte for a period of time to develop into a seed. Life Cycle of the Cycads Male reproductive stucture, pollen is dispersed by wind or insects to female reproductive structure. (haploid) gynostrobilus grows a pollen tube, sperm cell swims through pollen tube using its tail, or flagella. (haploid )This fertilizes the egg and it becomes a zygote. (Dipoid) Zygote develops into an embryo then a seed is developed in a coat that originates from the ovary. (diploid) Development of the microspores and megaspores through meiosis (haploid) Then the tree grows! (diploid) Economic and health benefits of Cycads •Some cycads are poisonous as a result there are not many medical benefits •These are also very close to extinction •If prepared correctly they can be eaten •The nuts contain a nerve toxin •Consumption of the starch derived from cycads is a factor in the development of Lytico-Bodig disease, a disease symptoms similar to Parkinson's and ALS. •But they look kinda pretty!! Thank You…