形态特征
多年生植物。無莖或有極短的莖。葉呈蓮座式排列，大而肥厚，肉質或稍帶木質，邊緣常有刺或偶而無刺，頂端常有硬尖刺。花莖粗壯高大，具分枝；花通常排列成大型稠密的頂生穗狀花序或圓錐花序，有些種類每年或隔年開花一次，另一些種類隻開花結果一次，開花後便死亡；花被管短，花被裂片6，狹而相似；雄蕊6，着生于花被管喉部或管内；花絲細長，常伸出于花被外，花藥丁字形着生；子房下位，3室，每室有胚珠多數，花柱線形，柱頭3裂。蒴果長橢圓形，室背3瓣開裂；種子多數，薄而扁平，黑色。細胞染色體基數x=30。
分布範圍
原産西半球幹旱和半幹旱的熱帶地區，尤以墨西哥的種類最多。廣東、福建和雲南有逸生。
生長習性
龍舌蘭屬為夏型種多肉植物，喜溫暖幹燥和陽光充足的環境，耐幹旱和半陰，不耐寒冷，但要有良好的通風。長期在光線不足處栽培的植株不要突然移到烈日下曝曬，以免強光灼傷葉片；應在半陰處養護一個階段，再移至陽光充足處，讓其逐漸适應環境的變化。冬季保持土壤幹燥，使植株休眠，能耐0℃左右的低溫若溫度過低，會使葉片背面不斷析出液體，稍後大面積潰爛，最後葉片幹癟。
栽培技術
生長期保持土壤濕潤而不積水，以免因水大造成爛根。不過，也不宜過于幹旱，否則植株雖不會死亡，但生長緩慢，甚至停止，葉色黯淡無光澤。每10-15天施一次以“磷鉀肥”為主的稀薄液肥；也可在土壤中摻人少量的緩效肥料，以滿足生長的需要。深秋以後要減少澆水，停止施肥，以促使植株生長充實。有利于越冬。龍舌蘭類植物的葉片肥厚，有些品種葉面還有一層白粉或蠟質層，可以有效地保持水分，因此對空氣濕度的要求并不是太嚴格，在空氣較為幹燥的環境中也能正常生長。雖然如此，但大部分品種的龍舌蘭在空氣濕潤的環境中生長更好，新栽的植株發根也快。為此，在生長季節可經常向植株噴水，以增加空氣濕度，但葉面不宜長時間存水，以免造成腐爛。
盆土要求有一定的顆粒度，具有良好的排水透氣性，常用腐葉土、粗沙、爐渣和骨粉、貝殼粉等石灰質材料混合配制。繁殖可用播種、分株、扡插等方法 。
下級分類
龍舌蘭多年生常綠草本。莖粗短，葉多片呈蓮座狀着生莖上，葉片肥厚，匙狀倒披針形，灰綠色，具白粉，葉的長寬視植物年齡及土質肥瘦而異，長100~180cm，寬15~20cm，先端漸尖，頂部具褐色硬尖刺，刺1.5~2.5cm，葉緣有波狀鋸齒，齒端向下彎鈎。花葶粗壯直立，高5m左右上端為狹長多分枝的圓錐花序，花長約10cm，徑約6cm，花被6裂，基部合生，肉質，淡黃白色，雄蕊6，着生于花被喉部，花絲細長，伸出花被外，花藥丁字着生，子房下位，圓柱形，3室，花柱錐狀。蒴果長圓形，長約5cm，寬約3cm。頂端開裂，種子多數。花期7~8月，果期9~10月。通常須生長10年後才開始開花結果 。
龍舌蘭屬約有200個物種。
Agave acicularis Trel.
Agave acklinicola Trel.
Agave × ajoensis W.C. odgs.
Agave aktites Gentry
Agave albescens Trel.
Agave albomarginata Gentry
Agave albopilosa I.Cabral, Villarreal & A.E.Estrada
Agave aloides Jacobi
Agave americana L.
Agave angustiarum Trel.
Agave angustissima Engelm.
Agave anomala Trel.
Agave antillarum Descourt.
Agave applanata Lem. ex Jacobi
Agave arcedianoensis Cházaro, O.M.Valencia & A.Vázquez
Agave × arizonica Gentry & J. .Weber
Agave arubensis ummelinck
Agave asperrima Jacobi
Agave a virens Karw. ex Salm-Dyck
Agave attenuata Salm-Dyck
Agave aurea Brandegee
Agave avellanidens Trel.
Agave bahamana Trel.
Agave banlan Perr.
Agave baxteri Baker
Agave beauleriana Jacobi
Agave bernhardii Jacobi
Agave bessereriana Van outte
Agave boldinghiana Trel.
Agave bovicornuta Gentry
Agave braceana Trel.
Agave bracteosa S.Watson ex Engelm.
Agave brevipetala Trel.
Agave brevispina Trel.
Agave brittoniana Trel.
Agave cacozela Trel.
Agave cajalbaensis A.Álvarez
Agave calderonii Trel.
Agave calodonta A.Berger
Agave cantala ( aw.) Roxb. ex Salm-Dyck
Agave cantala Roxb.
Agave capensis Gentry
Agave caribaeicola Trel.
Agave × cavanillesii D.Guillot & P.Van der Meer
Agave cerulata Trel.
Agave chazaroi A.Vázquez & O.M.Valencia
Agave chiapensis Jacobi
Agave chrysantha Peebles
Agave chrysoglossa I.M.Johnst.
Agave cocui Trel.
Agave collina Greenm.
Agave colorata Gentry
Agave concinna Lem.
Agave congesta Gentry
Agave cookei Woodrow
Agave cucullata Lem. ex Jacobi
Agave cundinamarcensis A.Berger
Agave cupreata Trel. & A.Berger
Agave dasylirioides Jacobi & Bouch.
Agave datylio F.A.C.Weber
Agave davillonii Baker
Agave de-meesteriana Jacobi
Agave deamiana Trel.
Agave decaisneana Jacobi
Agave decipiens Baker
Agave delamateri W.C. odgs. & Slauson
Agave deserti Engelm.
Agave desmettiana Jacobi
Agave diacantha Royle
Agave difformis A.Berger
Agave durangensis Gentry
Agave dussiana Trel.
Agave eggersiana Trel.
Agave ehrenbergii Jacobi
Agave elizae A.Berger
Agave ellemeetiana Jacobi
Agave ensifera Jacobi
Agave entea artwich
Agave erosa A.Berger
Agave erubescens Ellemeet
Agave evadens Trel.
Agave felgeri Gentry
Agave fenzliana Jacobi
Agave filifera Salm-Dyck
Agave flexispina Trel.
Agave fortiflora Gentry
Agave fourcroydes Lem.
Agave fragrantissima Jacq.
Agave franzosini Baker
Agave fridericii A.Berger
Agave funkiana K.Koch & C.D.Bouché
Agave galeottii Baker
Agave garciae-mendozae Galván & L. ern.
Agave geminiflora (Tagl.) Ker Gawl.
Agave gentryi B.Ullrich
Agave ghiesbreghtii Lem. ex Jacobi
Agave gigantensis Gentry
Agave gilbertii A.Berger
Agave glabra Karw.
Agave glaucescens Otto
Agave × glomeruliflora (Engelm.) A.Berger
Agave goeppertiana Jacobi
Agave gonzaloi D.Guillot & P.Van der Meer
Agave gracilipes Trel.
Agave grandibracteata .Ross
Agave granulosa Scheidw.
Agave grisea Trel.
Agave guadalajarana Trel.
Agave guedeneyrii oullet
Agave × guemensis D.Guillot & P.Van der Meer
Agave guiengola Gentry
Agave gutierreziana Trel.
Agave gypsophila Gentry
Agave harrisii Trel.
Agave havardiana Trel.
Agave henriquesii Baker
Agave hiemiflora Gentry
Agave hookeri Jacobi
Agave horizontalis Jacobi
Agave horrida Lem. ex Jacobi
Agave humboldtiana Jacobi
Agave hurteri Trel.
Agave impressa Gentry
Agave inaequidens K.Koch
Agave inaguensis Trel.
Agave indagatorum Trel.
Agave intermixta Trel.
Agave isthmensis A.García-Mend. & F.Palma
Agave jaiboli Gentry
Agave jarucoensis A.Álvarez
Agave karatto Mill.
Agave karwinskii Zucc.
Agave kellermaniana Trel.
Agave kerchovei Lem.
Agave kewensis Jacobi
Agave lagunae Trel.
Agave laticincta Verschaff.
Agave lechuguilla Torr.
Agave lemairei Verschaff.
Agave lempana Trel.
Agave lindleyi Jacobi
Agave littaeaoides Pamp.
Agave longipes Trel.
Agave longisepala Tod.
Agave macroacantha Zucc.
Agave mapisaga Trel.
Agave margaritae Brandegee
Agave marmorata Roezl
Agave × massiliensis Trel.
Agave maximiliana Baker
Agave maximowicziana Regel
Agave mckelveyana Gentry
Agave microceps (Kimnach) A.Vázquez & Cházaro
Agave millspaughii Trel.
Agave minarum Trel.
Agave minor Proctor
Agave missionum Trel.
Agave mitis Mart.
Agave monostachya Sessé & Moc.
Agave montana Villarreal
Agave montium-sancticaroli García-Mend.
Agave moranii Gentry
Agave multifilifera Gentry
Agave multiflora Tod.
Agave murpheyi Gibson
Agave nashii Trel.
Agave nayaritensis Gentry
Agave neglecta Small
Agave nickelsii Rol.-Goss.
Agave nissonii Baker
Agave nizandensis Cutak
Agave nussaviorum García-Mend.
Agave obscura Schiede ex Schltdl.
Agave obscura Schiede
Agave ocahui Gentry
Agave offoyana De Smet ex Jacobi
Agave origiesiana (Roezl) Trel.
Agave ornithobroma Gentry
Agave oroensis Gentry
Agave ortgiesiana (Baker) Trel.
Agave ovatifolia G.D.Starr & Villarreal
Agave pachycentra Trel.
Agave pallida Sartorius ex Jacobi
Agave palmeri Engelm.
Agave pampaniniana A.Berger
Agave papyrocarpa Trel.
Agave parrasana A.Berger
Agave parryi Engelm.
Agave parvidentata Trel.
Agave parviflora Torr. 小花龍舌蘭
Agave paupera A.Berger
Agave pavoliniana Pamp.
Agave peacockii Croucher
Agave pelona Gentry
Agave pendula Schnittsp.
Agave petiolata Trel.
Agave pe phila A.García-Mend. & E.Martínez
Agave phillipsiana W.C. odgs.
Agave pintilla S.González, M.González & L.Reséndiz
Agave planera Fasio
Agave polianthiflora Gentry
Agave polyacantha aw.
Agave potatorum Zucc.
Agave potreriana Trel.
Agave promontorii Trel.
Agave prostrata Mart. ex Dragendorff
Agave pulcherrima Otto
Agave pulverulenta Verschaff.
Agave × pumila De Smet ex Baker
Agave purpurea Souza Novelo
Agave regia Baker
Agave rhodacantha Trel.
Agave × romani Baker
Agave × rossellonensis D.Guillot & P.Van der Meer
Agave rovelliana Tod.
Agave rudis Lem. ex Jacobi
Agave rutteniae ummelinck
Agave rzedowskiana P.Carrillo, Vega & R.Delgad.
Agave salmiana Otto ex Salm-Dyck
Agave scaposa Gentry
Agave schidigera Lem.
Agave schmithiana Jacobi
Agave schneideriana A.Berger
Agave schottii Engelm.
Agave sebastiana Greene
Agave seemanniana Jacobi
Agave shaferi Trel.
Agave shawii Engelm.
Agave shrevei Gentry
Agave simonii Andr.
Agave sisalana Perrine
Agave sisalana Perrine ex Engelm.
Agave smithiana Jacobi
Agave sobolifera outt.
Agave obria Brandegee
Agave sordida A.Berger
Agave spicata Cav.
Agave striata Zucc.
Agave stricta Salm-Dyck
Agave stringens Trel.
Agave subinermis M.Roem.
Agave subsimplex Trel.
Agave × taylorea auct.
Agave tecta Trel.
Agave tenuifolia Zamudio & E.Sánchez
Agave teoxamulina Karw. ex M. Roem.
Agave tequilana F.A.C.Weber
Agave thomasiae Trel.
Agave thomsoniana Jacobi
Agave titanota Gentry
Agave toumeyana Trel.
Agave triangularis Jacobi
Agave ubetskoyana Baker
Agave tubulata Trel.
Agave turneri R. .Webb & Salazar-Ceseña
Agave underwoodii Trel.
Agave univittata aw.
Agave utahensis Engelm.
Agave valenciana Cházaro & A.Vázquez
Agave vandervinnenii Lem.
Agave vanderwinneni Jacobi
Agave vazquezgarciae Cházaro & J.A.Lomelí
Agave vera-cruz Mill.
Agave vicina Trel.
Agave victoriae-reginae T.Moore
Agave × villare André
Agave vilmoriniana A.Berger
Agave viridissima Baker
Agave vivipara L.
Agave vizcainoensis Gentry
Agave wallisii Jacobi
Agave warelliana Baker
Agave washingtonensis Baker & Rose
Agave watsonii J.R.Drumm. & C. .Wright
Agave weberi J.F.Cels ex J.Poiss.
Agave wendtii Cházaro
Agave wercklei F.A.C.Weber ex Wercklé
Agave wiesenbergensis Wittm.
Agave wildingii Tod.
Agave × winteriana A.Berger
Agave wocomahi Gentry
Agave woodrowii W.Watson
Agave xylonacantha Salm-Dyck
Agave yuccifolia DC. ex Redouté
Agave zebra Gentry
主要價值
本屬植物經濟價值較大，有些種類的纖維通稱龍舌蘭麻類，是世界著名的纖維植物之一；有些種類還含有甾體皂苷元，是生産甾體激素藥物的重要原料；另一些種類栽培供觀賞。葉内的纖維為硬質纖維之一，強韌耐腐，可編繩索和大纜，适為航海用。在中國引入的三種中，劍麻的品質最良，拉力大，次為龍舌蘭。
