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54. Morinda Linnaeus, Sp. Pl. 1: 176. 1753.

巴戟天属 ba ji tian shu

Authors: Tao Chen & Charlotte M. Taylor

Rojoc Adanson.

Lianas, climbing shrubs, erect shrubs, or small trees, rarely dioecious, sometimes with spines; branching sometimes sylleptic with growth continued from an axillary or subapical node, with lateral branches sometimes surrounded at base by persistent leafless stipules. Raphides present. Leaves opposite, rarely ternate, or sometimes anisophyllous and apparently 1 at flowering nodes, sometimes with domatia in axils of secondary and occasionally tertiary veins, margins rarely sinuate-undulate or lyrate; stipules persistent or infrequently caducous, interpetiolar, united around stem, or fused to petioles, triangular, entire. Inflorescences terminal, axillary, or leaf-opposed, capitate with 1 to several hemispherical to subglobose heads, these fasciculate or cymose, few to many flowered, pedunculate or sessile, bracteate or bracts reduced. Flowers sessile, shortly to fully fused by their ovaries [to free or nearly so], bisexual and distylous, rarely bisexual and monomorphic, or rarely dioecious. Calyx limb truncate to sinuate or rarely in 1-3 flowers of an inflorescence with 1 petaloid calycophyll (Morinda citrifolia). Corolla white or pink, funnelform, salverform, or campanulate, inside glabrous or pubescent in throat, [tube sometimes fenestrate]; lobes 3-7, valvate in bud. Stamens 3-7, inserted in corolla throat or tube, exserted or included; filaments short; anthers dorsifixed, sometimes with connective prolonged into an apical appendage. Ovary 2-celled with ovules 2 in each cell, or incompletely to completely 4-celled due to secondarily formed false septa with ovules 1 in each cell, ovules attached to septum near base; stigmas 2, linear, exserted or included. Fruit multiple with entire fruiting heads comprising one fruit (i.e., drupecetum) [sometimes fruit simple]; individual fruit drupaceous, fleshy, generally obovoid, blue to black, with calyx limb persistent; pyrenes 2-4, 1-locular, with 1 seed, cartilaginous or bony, subtrigonous to plano-convex, adaxially (i.e., ventrally) flat or sulcate; seeds medium-sized, subtrigonous or ellipsoid; endosperm abundant, corneous; embryo small; cotyledons oblong; radicle inferior.

About 80-100 species: widespread in tropical and subtropical regions worldwide; 27 species (18 endemic) in China.

Morinda includes a notable range of breeding systems (Johansson, Opera Bot. 122: 1-167. 1994), but most of the species are apparently distylous, with the anthers and stigmas separated and their positions reciprocal between the short-styled and long-styled form of the same species; however, this biology has been sometimes overlooked. Also, as noted by Johansson (loc. cit.), the position of the inflorescences, in particular terminal vs. leaf-opposed, deserves careful observation and aids identification of species. In particular, the leaf-opposed inflorescences often are produced on the terminal node, then later displaced by subsequent growth from the axil of that leaf, and can be confused with true terminal inflorescences that have two subtending leaves. The inflorescences with "fasciculate to umbellate" peduncles actually appear to be condensed cymes or racemes, with the peduncles arising from a very shortly prolonged structure at the stem apex that also bears several stipuliform bracts, usually one above the other. The twining Asian species apparently share having their lateral branches surrounded at the base (i.e., at the divergence from main stem) by persistent leafless stipules. Some species of Morinda have petaloid bracts or possibly calyx lobes; this character appears to vary within some individual species. Y. Z. Ruan’s (in FRPS 71(2): 179-202. 1999) taxonomy of Morinda distinguished species based on different characters, in particular pubescence, leaf shape, peduncle length compared across developmental stages, drying color and texture, pattern of tertiary leaf veins on dried specimens, and degree of fusion of flowers, than used by many other authors (e.g., Johansson, loc. cit.; Springate et al., Fl. Bhutan 2(2): 804. 1999).

1 Erect trees or shrubs; inflorescences terminal, axillary, or leaf-opposed, 1 or 2 per node   (2)
+ Lianas, twiners, or subshrubs; inflorescences terminal, with heads solitary or in groups of 2-11   (8)
2 (1) Plants of seashores and low elevations, 0-50 m; leaves with 5-7 pairs of secondary veins; fruit 2.5-5 cm in diam.   6 M. citrifolia
+ Plants of terrestrial inland habitats, 500-1400 m (exact elevation unknown in M. leiantha)   (3)
3 (2) Inflorescences terminal and/or axillary   (4)
+ Inflorescences leaf-opposed   (5)
4 (3) Stems hirtellous, hispidulous, or subglabrous; leaves with secondary veins 5-8 pairs; peduncles 0.2-0.5 cm; corollas with tubes ca. 20 mm and lobes ca. 4 mm.   13 M. leiantha
+ Stems glabrous or subglabrous; leaves with secondary veins 8-10 pairs; peduncles ca. 2 cm; corollas with tubes ca. 32 mm and lobes ca. 13 mm.   15 M. longissima
5 (3) Stems glabrous to pubescent; leaves pubescent abaxially, with secondary veins 7-10 pairs; peduncles 0.1-0.3 cm.   19 M. persicifolia
+ Stems glabrous; leaves glabrous abaxially, with secondary veins 9-24 pairs; peduncles 1-6 cm   (6)
6 (5) Leaves 4-5.5 cm wide, with secondary veins 12-24 pairs; corollas with tubes 15-18 mm, lobes 3-4 mm.   26 M. undulata
+ Leaves 5-11 cm wide, with secondary veins 9-14 pairs; corollas with tubes 16-33 mm, lobes 4-15 mm   (7)
7 (6) Petioles 0.5-1 cm; corollas with tubes 16-33 mm, lobes 4-15 mm; fruit ca. 2.5 cm in diam.   1 M. angustifolia
+ Petioles 2-4 cm; corollas with tubes ca. 22 mm, lobes ca. 4 mm; fruit ca. 1 cm in diam.   21 M. rosiflora
8 (1) Calyx limb developed, 1-2.5 mm; leaves acute to obtuse, rounded, truncate, or cordulate at base   (9)
+ Calyx limb reduced to shortly developed, less than 1 mm; leaves acute to cuneate, obtuse, or rounded at base   (12)
9 (8) Stems and leaves glabrous.   10 M. howiana
+ Stems and leaves glabrous to densely hirtellous or pilosulous, with pubescence present at least on veins abaxially on young leaves   (10)
10 (9) Stems and leaves sparsely to moderately puberulent to glabrescent; corollas with tubes and lobes ± equal, tube 3-4 mm, lobes 3-4 mm; fruit 0.5-1.1 cm in diam.   17 M. officinalis
+ Stems and leaves abaxially densely hirtellous or pilosulous; corollas with lobes longer than tube, tube 1-2 mm, lobes 3-4.5 mm; fruit 1-2 cm in diam   (11)
11 (10) Leaves with 7-10 pairs of secondary veins; corollas with tubes 1.5-2 mm and lobes 4-4.5 mm; calyx lobes narrowly triangular, acute.   8 M. cochinchinensis
+ Leaves with 10-13 pairs of secondary veins; corollas with tubes 1-1.2 mm and lobes 3-4 mm; calyx lobes rounded to obtuse.   27 M. villosa
12 (8) Leaves rugulose; corolla tube ca. 10 mm.   22 M. rugulosa
+ Leaves flat, smooth; corolla tube 1-3 mm or 12-25 mm   (13)
13 (12) Corolla tube 12-25 mm   (14)
+ Corolla tube 1-3 mm   (18)
14 (13) Corolla tube 12-20 mm   (15)
+ Corolla tube ca. 25 mm   (16)
15 (14) Young stems densely ferruginous hirtellous when dry; leaves drying leathery and abaxially whitened.   5 M. cinnamomifoliata
+ Young stems densely puberulent, strigillose, or hirtellous with pubescence drying colorless; leaves drying papery to membranous and abaxially golden yellow or brownish yellow.   7 M. citrina
16 (14) Leaves glabrous throughout.   3 M. brevipes
+ Leaves sparsely to densely pubescent at least abaxially on veins   (17)
17 (16) Stems puberulent with trichomes drying colorless, to glabrescent.   2 M. badia
+ Stems densely hirtellous with trichomes drying golden brown.   4 M. callicarpifolia
18 (13) Corollas with tubes and lobes ± equal in length, tube 2-2.5(-3) mm, lobes 2-2.5(-3) mm   (19)
+ Corollas with lobes longer than tubes by 50% or more, tube 1-2 mm, lobes 2-4 mm   (23)
19 (18) Stems and leaves glabrous.   12 M. lacunosa
+ Stems and leaves puberulent to hirtellous at least when young   (20)
20 (19) Leaves drying with gray to black cast.   14 M. litseifolia
+ Leaves drying with brown or yellow cast   (21)
21 (20) Leaves drying with brown cast; corollas with tubes ca. 3 mm, lobes ca. 3 mm.   24 M. shuanghuaensis
+ Leaves drying with brown, grayish brown, or yellowish brown cast; corollas with tubes 2-2.5 mm, lobes 2-2.5 mm   (22)
22 (21) Petioles 0.4-0.8 cm; leaves adaxially sparsely hispidulous to glabrescent.   11 M. hupehensis
+ Petioles 0.5-1.5 cm; leaves adaxially sparsely hirtellous, subglabrous, or glabrous.   23 M. scabrifolia
23 (18) Leaves drying with gray to black cast; stems densely yellowish, clear, or ferruginous strigillose or hirtellous.   9 M. hainanensis
+ Leaves drying with green, brown, yellow, or reddish cast; stems moderately to sparsely hirtellous, hispidulous, or puberulent with colorless trichomes, to subglabrous   (24)
24 (23) Leaves drying with yellow or reddish cast   (25)
+ Leaves drying with brown, grayish brown, or greenish cast   (26)
25 (24) Leaves 2-7 × 0.3-3 cm, cuneate to acute at base; corolla lobes 3-4 mm.   18 M. parvifolia
+ Leaves 7-13 × 2-4 cm, cuneate to obtuse or rounded at base; corolla lobes ca. 2 mm.   20 M. pubiofficinalis
26 (24) Leaves with secondary veins 4 or 5 pairs; peduncles 0.4-1.1 cm; fruit 0.4-0.8 cm in diam.   16 M. nanlingensis
+ Leaves with secondary veins 5-7 pairs; peduncles 1-1.5 cm; fruit 0.7-1.2 cm in diam.   25 M. umbellata

  • List of lower taxa


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