英國學(xué)生科學(xué)讀本 Lesson 74 蒲公英(2)

In spring, some hollow flower-stalks grow up from the centre of the rosette of leaves. Each stalk bears what looks like one large yellow flower. But if you pull one of these flower-heads to pieces, you will find that it is really made up of a great many small separate flowers, which all grow close together on the cushion-shaped top of the flower-stalk.

春天來臨之際, 有些葉子的蓮座叢中間會長出空心的花葶。每一根花葶頭上都好像頂著一朵巨大的黃花。然而, 如果你將這樣一個頭狀花序分解開來, 就會發(fā)現(xiàn), 它其實由許多獨立的小花構(gòu)成, 它們?nèi)可L在花莖的墊狀頂部, 彼此緊密依靠在一起。

Outside the large flower-head is a double row of small green leaves, which protected the tiny flowers within when the "head" was only a bud. These small leaves look somewhat like the green cup or calyx which covers the young buds of single flowers. But they are really quite different.

巨大的頭狀花序外面長有兩排小綠葉, 它們能夠在“頭狀花序”只是蓓蕾時保護(hù)深藏其中的幼年小花。這些葉子看起來就像是綠色的杯子或者說是包裹著單生花的花蕾的花萼, 不過它們之間的區(qū)別很大。

If we pull off some of the many small yellow flowers or florets that make up the flower-head, and look at them very carefully, we shall see that each has an outside fringe of white hairs. These hairs are really the calyx or outer cup of the tiny flower; and although they do not seem to be of any use to it now, we shall see that they are of much use by-and-by. The little flower itself is a narrow tube, one side of which grows out into a long yellow ribbon.

取下幾朵黃色的小花仔細(xì)觀察, 就會發(fā)現(xiàn), 每一只花朵外面都長有白色細(xì)絲狀的邊緣結(jié)構(gòu)。這些才是真正的花萼;雖然現(xiàn)在它們看起來沒什么作用, 不過我們逐漸就會了解到它們的重要功能。小花本身呈狹窄的管狀結(jié)構(gòu), 其中一側(cè)發(fā)育成為長長的黃色帶狀物。

Inside this tube are five very small dust-spikes, all growing together, and forming another and smaller tube. In the centre of the flower is the seed- vessel. At the bottom it is round and white like a little bag. From the top the slender yellow style rises, pushing two rough curving horns out beyond the flower-tube. These horns are ready to catch any pollen dust that insects may bring.

這個管狀結(jié)構(gòu)內(nèi)部則是五個非常細(xì)小的雄蕊, 彼此緊靠在一起, 構(gòu)成另外一個更小的管狀結(jié)構(gòu)?；ǘ渲虚g則是種皮。底部是一個白色的袋裝結(jié)構(gòu)。頂部則長有細(xì)細(xì)的黃色花柱, 兩個不平整的卷曲突起伸展而出, 扎根于花冠筒的上方。這兩個突起隨時準(zhǔn)備捕捉昆蟲傳播過來的花粉。

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