???? long xue shu shu
Chen Xinqi (??? Chen Sing-chi); Nicholas J. Turland
Plants treelike, shrubby, or subshrubby. Stems simple or branched, ± woody. Leaves crowded toward apex of stems or spaced along distal part of stems, sessile or petiolate; petiole to 8 cm, base amplexicaul; leaf blade usually sword-shaped to elliptic-lanceolate, veins truly parallel from base, lateral veins absent. Inflorescence terminal, branched, rarely simple. Flowers bisexual, clustered, sometimes solitary; pedicel articulate. Perianth cylindric, campanulate, or funnelform; tube short; lobes 6, similar. Stamens 6, inserted in tube or throat of perianth; anthers versatile. Ovary 3-loculed; ovules 1 or 2 per locule. Style slender; stigma capitate or 3-lobed. Fruit a berry, globose, 1--3-seeded. Seeds not coated with phytomelanin.
About 50 species: mainly in tropical regions of Africa and Asia; six species in China.
Dracaena, as treated in Dracaenaceae by Bos (in Kubitzki, Fam. Gen. Vasc. Pl. 3: 240. 1998), includes the genus Sansevieria Thunberg from Africa to S Asia. If this arrangement is accepted, Dracaena probably comprises from 100--150 species. Dracaena in Asia has been studied very little for several decades. Consequently there are many taxononomic and nomenclatural problems and large numbers of unidentified specimens in herbaria. The present account attempts to identify some of the problems affecting the Chinese species, which can only be properly understood in the context of an in-depth study on the genus throughout tropical Asia.
1 Plants treelike, 3--15 m tall; leaves crowded toward apex of stems, base completely covering internode; internodes much shorter than wide; flowers in clusters of 2--7, perianth 6--8 mm. (2)
+ Plants shrubby or subshrubby, to 5 m tall; leaves spaced along distal part of stems, base usually not completely covering internode; internodes often longer than wide; flowers solitary or in clusters of 2--4, perianth (14--)18--23 mm. (3)
2 (1) Branches reddish apically; leaves reddish basally; inflorescence rachis densely papillose-pubescent; filaments reddish brown tuberculate distally 1 DRACAENA cochinchinensis
+ Branches not reddish apically; leaves not reddish basally; inflorescence rachis glabrous or subglabrous; filaments not tuberculate 2 DRACAENA cambodiana
3 (1) Leaves subsessile or indistinctly petiolate, petiole to 1 cm, leaf blade nearly sword-shaped to linear-oblanceolate 3 DRACAENA angustifolia
+ Leaves distinctly petiolate, petiole 1--8 cm, leaf blade linear-lanceolate to elliptic or broadly oblanceolate. (4)
4 (3) Leaf blade linear-lanceolate or narrowly elliptic-lanceolate, 10--15 × 2--3 cm; base of petiole neither enlarged nor sheathing internode 4 DRACAENA elliptica
+ Leaf blade elliptic-lanceolate, elliptic, or broadly oblanceolate, 20--40 × 6--8 cm; base of petiole enlarged and sheathing internode. (5)
5 (4) Plants shrubby, to 5 m tall; inflorescence branched, 30--60 cm; pedicels 8--10 mm, articulate at middle 5 DRACAENA hokouensis
+ Plants subshrubby, less than 1 m tall; inflorescence simple, ca. 15 cm; pedicels 3--4 mm, articulate above middle 6 DRACAENA terniflora