常綠喬木或灌(guan)木;小枝不規則互生(sheng),基(ji)部(bu)有(you)(you)多(duo)數(shu)(shu)或少數(shu)(shu)宿存的(de)芽鱗,稀(xi)全部(bu)脫(tuo)落(luo);冬芽芽鱗覆瓦狀(zhuang)(zhuang)排(pai)列(lie)(lie),背部(bu)縱脊明(ming)顯(xian)(xian)或不明(ming)顯(xian)(xian)。葉(xie)條形(xing),螺旋狀(zhuang)(zhuang)著生(sheng),基(ji)部(bu)扭轉(zhuan)排(pai)成(cheng)(cheng)(cheng)二列(lie)(lie),直或鐮狀(zhuang)(zhuang),下延生(sheng)長,上(shang)面(mian)中脈隆起,下面(mian)有(you)(you)兩條淡(dan)灰色(se)、灰綠色(se)或淡(dan)黃(huang)色(se)的(de)氣(qi)孔帶,葉(xie)內(nei)無(wu)樹脂道。雌雄(xiong)異株,球(qiu)花單生(sheng)葉(xie)腋;雄(xiong)球(qiu)花圓球(qiu)形(xing),有(you)(you)梗(geng),基(ji)部(bu)具覆瓦狀(zhuang)(zhuang)排(pai)列(lie)(lie)的(de)苞(bao)片,雄(xiong)蕊6-14枚(mei),盾狀(zhuang)(zhuang),花藥4-9,輻(fu)射排(pai)列(lie)(lie);雌球(qiu)花幾(ji)無(wu)梗(geng),基(ji)部(bu)有(you)(you)多(duo)數(shu)(shu)覆瓦狀(zhuang)(zhuang)排(pai)列(lie)(lie)的(de)苞(bao)片,上(shang)端(duan)2-3對苞(bao)片交叉(cha)對生(sheng),胚(pei)珠直立,單生(sheng)于總花軸上(shang)部(bu)側生(sheng)短軸之頂端(duan)的(de)苞(bao)腋,基(ji)部(bu)托以圓盤狀(zhuang)(zhuang)的(de)珠托,受精后珠托發育成(cheng)(cheng)(cheng)肉(rou)質(zhi)(zhi)、杯(bei)狀(zhuang)(zhuang)、紅色(se)的(de)假(jia)種(zhong)(zhong)皮(pi)。種(zhong)(zhong)子堅果狀(zhuang)(zhuang),當年(nian)成(cheng)(cheng)(cheng)熟,生(sheng)于杯(bei)狀(zhuang)(zhuang)肉(rou)質(zhi)(zhi)的(de)假(jia)種(zhong)(zhong)皮(pi)中,稀(xi)生(sheng)于近膜(mo)質(zhi)(zhi)盤狀(zhuang)(zhuang)的(de)種(zhong)(zhong)托(即未發育成(cheng)(cheng)(cheng)肉(rou)質(zhi)(zhi)假(jia)種(zhong)(zhong)皮(pi)的(de)珠托)之上(shang),種(zhong)(zhong)臍(qi)明(ming)顯(xian)(xian),成(cheng)(cheng)(cheng)熟時(shi)肉(rou)質(zhi)(zhi)假(jia)種(zhong)(zhong)皮(pi)紅色(se),有(you)(you)短梗(geng)或幾(ji)無(wu)梗(geng);子葉(xie)2枚(mei),發芽時(shi)出土。
主要用途
本(ben)屬木材(cai)(cai)的(de)邊材(cai)(cai)窄,與(yu)心材(cai)(cai)區別明顯,無(wu)樹(shu)(shu)脂道(dao)及樹(shu)(shu)脂細胞,紋理均勻(yun),結構細致,硬度大,防腐(fu)力強(qiang),韌性(xing)(xing)強(qiang)。為優(you)(you)良(liang)(liang)的(de)建筑、橋梁、家具(ju)、器(qi)材(cai)(cai)等用(yong)材(cai)(cai)。惟(wei)產量少,一般僅作細木加(jia)工、船槳、拱(gong)形制品、車旋、雕刻、樂器(qi)及箱板等用(yong);種(zhong)(zhong)子可榨油。葉常綠,深綠色,假種(zhong)(zhong)皮肉(rou)質紅(hong)色,頗為美觀,可作庭(ting)園樹(shu)(shu)。本(ben)屬樹(shu)(shu)種(zhong)(zhong)耐蔭性(xing)(xing)強(qiang),在天(tian)然林(lin)中生長緩慢,分布星散,野生樹(shu)(shu)木日漸減少。惟(wei)木材(cai)(cai)優(you)(you)良(liang)(liang),宜選(xuan)用(yong)造林(lin),加(jia)強(qiang)撫育管理,可促進其加(jia)速(su)生長,以生產優(you)(you)良(liang)(liang)木材(cai)(cai)。