常綠喬(qiao)木(mu)或灌木(mu);小枝不規則互生(sheng)(sheng),基(ji)部(bu)(bu)(bu)(bu)(bu)有(you)多數(shu)或少(shao)數(shu)宿(su)存的(de)(de)(de)(de)芽鱗,稀全部(bu)(bu)(bu)(bu)(bu)脫(tuo)落;冬(dong)芽芽鱗覆瓦(wa)狀(zhuang)排列(lie)(lie),背部(bu)(bu)(bu)(bu)(bu)縱脊(ji)明(ming)(ming)顯(xian)或不明(ming)(ming)顯(xian)。葉(xie)條形(xing),螺(luo)旋(xuan)狀(zhuang)著(zhu)生(sheng)(sheng),基(ji)部(bu)(bu)(bu)(bu)(bu)扭轉排成(cheng)二列(lie)(lie),直(zhi)或鐮狀(zhuang),下延生(sheng)(sheng)長,上面中脈隆(long)起(qi),下面有(you)兩條淡(dan)灰色(se)、灰綠色(se)或淡(dan)黃色(se)的(de)(de)(de)(de)氣孔帶,葉(xie)內(nei)無樹脂道。雌雄(xiong)異株,球花(hua)單(dan)生(sheng)(sheng)葉(xie)腋;雄(xiong)球花(hua)圓(yuan)球形(xing),有(you)梗,基(ji)部(bu)(bu)(bu)(bu)(bu)具覆瓦(wa)狀(zhuang)排列(lie)(lie)的(de)(de)(de)(de)苞片(pian),雄(xiong)蕊6-14枚,盾狀(zhuang),花(hua)藥(yao)4-9,輻射排列(lie)(lie);雌球花(hua)幾(ji)無梗,基(ji)部(bu)(bu)(bu)(bu)(bu)有(you)多數(shu)覆瓦(wa)狀(zhuang)排列(lie)(lie)的(de)(de)(de)(de)苞片(pian),上端2-3對(dui)苞片(pian)交叉對(dui)生(sheng)(sheng),胚珠直(zhi)立,單(dan)生(sheng)(sheng)于(yu)總花(hua)軸上部(bu)(bu)(bu)(bu)(bu)側生(sheng)(sheng)短(duan)軸之頂端的(de)(de)(de)(de)苞腋,基(ji)部(bu)(bu)(bu)(bu)(bu)托(tuo)以(yi)圓(yuan)盤狀(zhuang)的(de)(de)(de)(de)珠托(tuo),受精后珠托(tuo)發(fa)育成(cheng)肉質、杯(bei)狀(zhuang)、紅(hong)(hong)色(se)的(de)(de)(de)(de)假種(zhong)(zhong)(zhong)皮(pi)。種(zhong)(zhong)(zhong)子堅果狀(zhuang),當(dang)年成(cheng)熟(shu),生(sheng)(sheng)于(yu)杯(bei)狀(zhuang)肉質的(de)(de)(de)(de)假種(zhong)(zhong)(zhong)皮(pi)中,稀生(sheng)(sheng)于(yu)近膜質盤狀(zhuang)的(de)(de)(de)(de)種(zhong)(zhong)(zhong)托(tuo)(即未(wei)發(fa)育成(cheng)肉質假種(zhong)(zhong)(zhong)皮(pi)的(de)(de)(de)(de)珠托(tuo))之上,種(zhong)(zhong)(zhong)臍明(ming)(ming)顯(xian),成(cheng)熟(shu)時肉質假種(zhong)(zhong)(zhong)皮(pi)紅(hong)(hong)色(se),有(you)短(duan)梗或幾(ji)無梗;子葉(xie)2枚,發(fa)芽時出土。
主要用途
本屬木(mu)材(cai)的(de)邊材(cai)窄,與心(xin)材(cai)區別明顯,無樹脂道及(ji)樹脂細(xi)胞,紋理均勻,結(jie)構(gou)細(xi)致,硬度(du)大(da),防腐(fu)力強(qiang),韌性(xing)強(qiang)。為優(you)良(liang)的(de)建筑、橋梁(liang)、家具、器材(cai)等用(yong)材(cai)。惟產量(liang)少(shao),一(yi)般僅(jin)作細(xi)木(mu)加工、船槳、拱形制品、車旋、雕(diao)刻、樂(le)器及(ji)箱板等用(yong);種子可榨(zha)油。葉(xie)常綠,深綠色(se),假(jia)種皮肉(rou)質(zhi)紅色(se),頗為美觀,可作庭園樹。本屬樹種耐蔭性(xing)強(qiang),在天然林(lin)(lin)中生長緩(huan)慢,分布星散,野(ye)生樹木(mu)日漸(jian)減少(shao)。惟木(mu)材(cai)優(you)良(liang),宜(yi)選用(yong)造林(lin)(lin),加強(qiang)撫(fu)育管理,可促進其(qi)加速(su)生長,以生產優(you)良(liang)木(mu)材(cai)。