生物競賽講座之裸子植物-資料下載頁
2025-01-16 18:56本頁面
【正文】 tures. 18:28 35 Sporophylls and microsporangia of the pollenbearing cones of a yew. Ovulate cones and pollenbearing cones are found on separate individual. The seeds and leaves of yews contain a toxic substance and are an important cause of poisoning by plants in children in the United States, although fatalities are extremely rare. 18:28 36 二、分類 3科， 14屬， 162種；我國產(chǎn) 3科， 7屬， 33種。 羅漢松科 （ Podocarpaceae） 三尖杉科 （ Cephalotaceae） 紅豆杉科 （ Taxaceae） 葉 條形、披針形，螺 旋狀排列 條形、披針形， 交互對生 條形、披針形，螺旋 狀排列或交互對生 小孢子葉具小孢子囊數(shù)目 2個小孢子囊 2－ 4 個小孢子囊 3－ 9 個小孢子囊 小孢子 具氣囊，多細(xì)胞時 傳粉 無氣囊，多細(xì)胞 時傳粉 無氣囊，單細(xì)胞時傳 粉 大孢子葉 套被 珠托 珠托 種子 具肉質(zhì)或革質(zhì)的假 種皮，具種托 具肉質(zhì)的假種皮 具肉質(zhì)而鮮紅的假種 皮 18:28 37 買麻藤綱（ Gopsida）的代表植物 18:28 38 小葉買麻藤（ Gum parvifolium） 18:28 39 The gophyte Welwitschia mirabilis, found only in the Namib Desert of Namibia and adjacent regions of southwestern Africa. Welwitschia produces only two leaves, which continue to grow for the life of the plant. As growth continues, the leaves break off at the tips and split lengthwise。 thus older plants appear to have numerous leaves. 18:28 40 a) A male shrub of Ephedra viridis, in California. It is a densely branched shrub that has scalelike leaves, like other members of the genus. b) Microsporangiate strobili of E. virdis. Note the scalelike leaves on the stem. c) Ephedra trifurca, in Arizoma, with Microsporangiate strobili . 18:28 41 Female plant of Ephedra viridis, with seeds. 18:28 42 謝謝！
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