苔(moss)
苔藓植物门苔纲小型陆上孢子植物,至少10,000种。早在二叠纪(2.9亿年至2.48亿年前)就已存在,分布於全世界各地除海水外的地区。常见於潮湿阴暗的地方(如森林地面),苔类大小不一,小者只能用显微镜观察,大者长达1公尺以上。苔类可防止侵蚀作用,并释出养分。其生活史显示清楚的有性配子体(茎状和叶状结构产生卵子和游动的精子)和孢子体(包含直立的茎状蒴柄,其终端为孢子囊)之间的世代交替现象。苔类也可藉分枝进行无性生殖。有重要经济价值的苔类是泥炭苔属的种,可形成泥炭。有许多植物也称作moss,但它们实际上不是苔类。如爱尔兰苔(Irish moss)是一种红藻;冰岛苔(Iceland moss)、橡苔(oak moss)和驯鹿苔(reindeer moss)都是地衣;西班牙苔(Spanish moss)既指一种地衣,又指一种凤梨科气生植物。石松(club moss)是石松科常绿草本植物。
English version:
moss
Any of at least 10,000 species of small, spore-bearing land plants in the bryophyte division, found worldwide except in salt water since the Permian period (290-248 million years ago). Commonly found in moist, shady locations (e.g., forest floors), mosses may range in size from microscopic forms to plants more than 40 in. (1 m) long. They prevent erosion and release nutrients. The life cycle shows clear alternation of generations between the sexual gametophyte, with stemlike and leaflike structures that produce eggs and swimming sperm, and the sporophyte, a raised stalk that ends in a spore case (sporangium). Mosses also reproduce asexually by branching. The economically important genus Sphagnum forms peat. Many so-called mosses are not bryophytes, including Irish moss (a red form of algae); beard moss, Iceland moss, oak moss, and reindeer moss (all lichens); Spanish moss (a name used variously for a lichen or an air plant of the pineapple family); and club moss (an evergreen herb of the family Lycopodiaceae).