雲林莞草為本省水田多年生之新雜草，曾出現於屏東、台南、雲林、彰化、台中等縣之水田上，尤其以彰化縣濱海各鄉鎮密度最高，為害最烈。雲林莞草主要以球莖繁殖，由於其生長快速，繁殖力強，對殺草劑之忍受性高，已被世界各國列為頑強之水田雜草之一。本試驗即針對雲林莞草在本省第一期作氣候條件下之生長型態作一初步之探討，其結果如下：1.雲林莞草之株高於發芽後急速生長，至發芽後48天即可達85公分，之後維持在90-100公分間。其主莖上之葉片數亦在發芽後急速增加，至發芽後27天已達9片，之後維持於9-10片間，在發芽後55天，由於葉片逐漸黃化，而呈現緩慢下降之趨勢。2.雲林莞草之分蘗數於發芽後急速增加，至發芽後48天已達130支，而後呈現穩定之現象。至發芽後69天時，分蘗數達到最高之181支。3.雲林莞草之葉面積於發芽後急速增加，至發芽後55天達到最高(3650.9cm2)，而後隨著葉片之老化，葉面積逐漸減少。4.雲林莞草之開花於發芽後20天即可在少數植株上發現，在後逐漸增加，至發芽後41天全部植株均已開花。5.雲林莞草之乾物質生產量(全株乾重)在發芽後急速增加，至發芽後69天呈現緩慢增加之趨勢。就其地上部與地下部之乾物質分配而言，生育初期，地上部乾物質所佔全株乾重比例逐漸增加，地下部乾物質所佔全株乾重比例逐漸減少，至發芽後41天，才呈現相反之趨勢，於此同時，地下部亦有類似球莖之組織產生。6.雲林莞草於發芽後41天，地下部有類似球莖之組織產生，而後數目逐漸增加，至發芽後90天，已達266個，而在120天的生長下，雲林莞草球莖繁殖數高達460倍。綜合言之，雲林莞草早期生長以營養生長為主，此時期對水稻極具競爭性，後期則以繁殖球莖為主。

Bulrush (Scirpus maritimus L.) is a destructive perennial weedinpaddy-field, and it grows widely in Pingtung, Tainan, Yun1in,Changhua and Taichung counties in Taiwan. Especially along thecoastal areas of Changhua county. The high density of weed populationcan cause severe infection. It is difficu1t to control due to thefast growing habit and high multiplication rate. Since it reproduceshy bulbs it is highly t01erant to herbicide. The growth pattern ofbulrush at first-crop season in Taichung DAIS is describedasfollows 1. These p1ants grow rapid1y after germination. The plantheight can reach 85 cm within 48 days after emergence (DAE), thenit maintains at 90-100 cm in height. The average number of leaveis about 10. The leave color turn to yellow after 55 DAE. 2. Themaximum number of tiller is 181 per plant recorded at 69 DAE. 3.The maximum leave area of bulrush is 3650.9cm2 at 55 DAE for inbulb. 4. Flower stalks appear at 20 DAE and completgeloy bloom art41 DAE. 5. The dry weight of bulrush reaches the highest level at90 DAp. The dry weight of above ground part increases faster thenthat of under ground part at ear1ier growth stage, but the oppositeresu1tis found at about 62 DAE. 6. The under ground part of bulblike tissues appears at 4] DAE. Totally, 266 small bulbs are foundat 90 DAE. The number of small bulbs can increase to 460 at 120DAE. 7. It is highly competitive with paddy rice due to the fastgrowth rate of vegetative part of this plant.