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88. Spiradiclis Blume, Bijdr. 975. 1826.

螺序草属 luo xu cao shu

Authors: Tao Chen & Charlotte M. Taylor

Herbs, annual or perennial, or subshrubs, unarmed. Raphides present. Leaves opposite, sometimes clustered and appearing whorled, rosulate, or pseudoverticillate, isophyllous to anisophyllous, without domatia; stipules persistent to caducous, interpetiolar, triangular, entire to 2(-5)-lobed. Inflorescences terminal and/or pseudoaxillary, cymose to paniculiform with axes slender and dichasial or often scorpioid, several to many flowered, pedunculate, bracteate or bracts reduced. Flowers sessile to pedicellate, bisexual, usually if not always distylous. Calyx with ovary portion usually 5-ridged or -winged, limb 5-lobed. Corolla white, pink, purple, or red, campanulate, funnelform, urceolate, or tubular, inside usually pubescent in throat and with pubescent ring near middle; lobes 5, in bud valvate or induplicate-valvate, often winged or keeled dorsally, sometimes notably pinnatinerved. Stamens 5, inserted below middle of corolla tube and included in long-styled flowers, inserted in throat or middle of corolla tube and partially exserted in short-styled flowers; filaments short to developed; anthers dorsifixed. Ovary 2-celled, ovules numerous in each cell on peltate axile placentas attached to middle of septum; stigmas 2-lobed, included to shortly exserted in long-styled flowers, included and positioned near middle of corolla tube in short-styled flowers. Fruit capsular, subglobose, often 5-ridged to -winged, with apical portion prolonged into beak, dehiscing loculicidally and often also simultaneously or subsequently septicidal from top, dividing partially to completely into 2 or 4 valves with walls usually persistent, papery to stiff, with calyx limb persistent, sometimes elongating; seeds numerous, small, angled; testa reticulate or alveolate; embryo minute; endosperm fleshy.

At least 40 species: Bhutan, China, India, Indonesia, Myanmar, Vietnam; 35 species (31 endemic, one of unconfirmed occurrence) in China.

Robbrecht (Opera Bot. Belg. 1: 1-271. 1988; Opera Bot. Belg. 6: 1-200. 1993) accepted earlier conclusions that Spiradiclis is related to Ophiorrhiza; a more recent study based on molecular data suggests that the situation may be more complex and calls into question the separation of these genera (Rydin et al., Pl. Syst. Evol. 278: 101-120. 2009). H. S. Lo (in FRPS 71(1): 86. 1999) described the corolla lobes as valvate in bud, but they were described as induplicate-valvate by Bakhuizen f. (Fl. Java 2: 289. 1965). This genus does not appear to be well known at all. It has only been studied regionally, in particular by H. S. Lo et al. (Acta Bot. Austro Sin. 1: 27-36. 1983), H. S. Lo (Bull. Bot. Res., Harbin 6(4): 31-53. 1986), Deb and Rout (Candollea 44: 225-229. 1989), H. S. Lo (Bull. Bot. Res., Harbin 18: 275-283. 1998), and R. J. Wang (Novon 12: 420-423. 2002). Ma et al. (J. Trop. Subtrop. Bot. 13(3): 264-270. 2005) studied seed morphology of sixteen Spiradiclis species and found partial correlation with the infrageneric classification of Lo.

H. S. Lo (loc. cit. 1998: 275-276) recognized two subgenera, distinguished as follows:

Spiradiclis subg. Spiradiclis: ellipsoid to linear-oblong capsules that are 2-4 × as long as wide and have straight valves, including eight (or possibly nine or ten) species in China;

Spiradiclis subg. Sinospiradiclis H. S. Lo: subglobose capsules that are ± as long as wide and have the valves ultimately twisted, including the remaining Chinese species.

One subsequently described species, Spiradiclis chuniana R. J. Wang, was not classified to subgenus when it was published because the fruit were unknown. The key here follows that of H. S. Lo in FRPS (71(1): 86-88. 1999), apparently intended as a schematic outline of the genus classification, with some changes: here the full range of variation that is given in the descriptions has been added to the key leads, and a few species have been moved to different sections within the key based on Lo’s descriptions. This key does not fully distinguish all the species; however, it cannot be improved on with the information now available and is here presented to summarize in English the existing information on Chinese Spiradiclis and to highlight problematic areas of its taxonomy.

1 Capsules narrowly ellipsoid, ellipsoid, oblanceoloid, narrowly oblong, or linear-oblong, 2-4 × as long as wide, with valves becoming twisted (dehiscence unknown in S. baishaiensis, S. laxiflora, S. longzhouensis) (S. subg. Spiradiclis)   (2)
+ Capsules subglobose, ellipsoid, to ovoid, or subglobose-obconic, ± as long as wide, valves remaining straight (fruit unknown in S. chuniana, S. corymbosa, S. ferruginea, S. fusca, S. longipedunculata, S. napoensis, S. rubescens, S. spathulata, S. xizangensis; fruit dehiscence unknown in S. hainanensis, S. longibracteata, S. oblanceolata, S. villosa) (S. subg. Sinospiradiclis)   (10)
2 (1) Capsules linear-oblong, oblanceoloid, or narrowly oblong, 2-4 × as long as wide, glabrous or puberulent   (3)
+ Capsules narrowly ellipsoid or ellipsoid, ca. 2 × as long as wide, glabrous, pilosulous, or villosulous   (6)
3 (2) Stems and leaves glabrous; petioles 3-4.5 cm; stipule unlobed.   23 S. "microcarpa"
+ Stems and abaxial leaf veins glabrescent, scaberulous, puberulent, villosulous, or strigillose; petioles 0.2-1 cm; stipules deeply 2-lobed   (4)
4 (3) Corolla tube 2-2.5 mm; corolla lobes apparently perhaps keeled dorsally; fruit 5-6 mm, with 2 valves or these later partly splitting.   4 S. caespitosa
+ Corolla tube 3-4 mm; corolla lobes smooth dorsally; fruit 2.5-4.5 mm with 4 valves   (5)
5 (4) Capsules 2.5-4 mm; stipules persistent.   1 S. arunachalensis
+ Capsules 4-4.5 mm; stipules caducous.   9 S. cylindrica
6 (2) Leaves tomentose or pilosulous at least abaxially; capsules glabrous to pilosulous or villous   (7)
+ Leaves glabrous; capsules glabrous   (8)
7 (6) Peduncle 5-9 cm; calyx lobes 3-4 mm, longer than fruit; capsules glabrous.   2 S. baishaiensis
+ Peduncle 0.1-0.5 cm; calyx lobes ca. 1 mm, shorter than fruit; capsules villosulous.   10 S. emeiensis
8 (6) Stems with 2 lines of dense hispidulous hairs.   22 S. malipoensis
+ Stems glabrous or sparsely evenly pubescent   (9)
9 (8) Leaves 10-15 cm, with secondary veins 9-11 pairs.   16 S. laxiflora
+ Leaves 15-21 cm, with secondary veins 16-23 pairs.   20 S. longzhouensis
10 (1) Leaves cordate, cordulate, subtruncate, or broadly obtuse at base   (11)
+ Leaves acute, cuneate, obtuse, or rounded at base   (15)
11 (10) Leaves 0.6-1.8 cm; plants creeping   (12)
+ Leaves 1.5-13 cm, at least some more than 1.8 cm; plants erect or creeping   (13)
12 (11) Calyx lobes 2-4 mm, in fruit 2 or 3 × as long as capsule.   13 S. guangdongensis
+ Calyx lobes 1.2-1.5 mm, in fruit ± equal to or shorter than capsule.   14 S. hainanensis
13 (11) Corolla 20-21.5 mm; leaves 1.5-4 cm; plants creeping.   33 S. umbelliformis
+ Corolla 6-9 mm; leaves 3-13 cm; plants ascending or acaulescent   (14)
14 (13) Plants with leaves distributed along developed stems; leaves 3-6.5 × 1.6-3 cm, broadly obtuse to truncate at base.   5 S. chuniana
+ Plants acaulescent or with short stems, with leaves often clustered at base of plant; leaves 5-13 × 2-5.5 cm, cordate or cordulate at base.   7 S. cordata
15 (10) Corolla with tube 13.5-23 mm   (16)
+ Corolla shorter, tube 2-9 mm (flowers unknown in S. bifida, S. villosa; only buds known in S. microphylla)   (26)
16 (15) Calyx lobes 1-1.5 mm, ± as long as or shorter than corolla "tube" (i.e., hypanthium portion together with unlobed basal part of calyx limb)   (17)
+ Calyx lobes 1.6-10 mm, longer than corolla "tube."   (18)
17 (16) Stems developed with leaves borne at developed internodes.   30 S. scabrida
+ Stems short or hardly developed, with leaves clustered at base.   31 S. spathulata
18 (16) Leaves glabrous on both surfaces; flowers dark red.   6 S. coccinea
+ Leaves pubescent (hirsute, pilose, strigose, hispidulous, hirtellous) on one or both surfaces and/or ciliate marginally; flowers red, bluish purple, white, purplish red, purplish white, or pink (flowers unknown in S. xizangensis)   (19)
19 (18) Corolla tube 19-22 mm   (20)
+ Corolla tube 12-18 mm (only known in bud in S. napoensis)   (22)
20 (19) Calyx lobes generally equal in size; leaves adaxially densely hispidulous-strigose; corolla bluish purple, tube 19-21 mm.   28 S. purpureocaerulea
+ Calyx lobes unequal in size; leaves adaxially sparsely puberulent or glabrous; corolla red or purplish red, tube 21-22 mm   (21)
21 (20) Secondary leaf veins 18-29 pairs; calyx lobes 3-10 mm; corolla tube ca. 22 mm.   18 S. longibracteata
+ Secondary leaf veins 9-11 pairs; calyx lobes 3.5-4.5 mm; corolla tube ca. 21 mm.   29 S. rubescens
22 (19) Calyx lobes unequal in length, one distinctly longer and/or wider than others; corolla tubes glabrescent or uniformly pubescent over broad areas inside   (23)
+ Calyx lobes equal or subequal in size; corolla tubes with 1 or 2 discrete white villous rings of pubescence inside   (24)
23 (22) Corolla pubescent inside; leaf secondary veins 8-15 pairs.   11 S. ferruginea
+ Corolla glabrescent inside; leaf secondary veins ca. 7 pairs.   35 S. xizangensis
24 (22) Leaves rounded, obtuse, or acute at apex, with 18-29 pairs of secondary veins; corolla sparsely purplish red pubescent outside; stipules broadly ovate.   18 S. longibracteata
+ Leaves acuminate at apex, with 6-10 pairs of secondary veins; corolla glabrous or with 5 lines of pubescence outside; stipules subulate to linear   (25)
25 (24) Leaves lanceolate, ovate, subelliptic, or subelliptic-oblong, yellowish brown on lower surface when dry; stipules and bracteoles 2-3 mm; corolla with 5 lines of pubescence outside, lobes narrowly winged on dorsal surface.   15 S. howii
+ Leaves narrowly ovate to broadly ovate, pale on lower surface when dry; stipules 2-8 mm and bracteoles 6-10 mm; corolla glabrous outside, lobes smooth on dorsal surface.   25 S. napoensis
26 (15) Stems and inflorescences glabrous   (27)
+ Stems and inflorescences pubescent   (30)
27 (26) Leaves narrowly elliptic-oblong or oblanceolate, 3.5-4.5 × as long as wide; stipules long triangular; stems with developed internodes.   26 S. oblanceolata
+ Leaves obovate, broadly obovate, oblong-elliptic, oblong-lanceolate, or subelliptic, 1.5-3 × as long as wide; stipules triangular, triangular-orbicular, suborbicular, or long triangular; stem internodes developed to reduced   (28)
28 (27) Stipules suborbicular or triangular-orbicular, cuspidate and 2-lobed; stem internodes developed.   19 S. longipedunculata
+ Stipules triangular to long triangular, at apex acuminate; stem internodes developed or reduced   (29)
29 (28) Leaves 1.5-3.5 cm wide, with 10-13 pairs of secondary veins; petioles 0.5-1.5 cm; corolla tube ca. 9 mm.   12 S. fusca
+ Leaves 3-4.5 cm wide, with 7-9 pairs of secondary veins; petioles 1-4 cm; corolla tube ca. 5 mm.   21 S. luochengensis
30 (26) Stems short, with leaves crowded at base of plant   (31)
+ Stems prolonged, erect to prostrate, with leaves separated by developed internodes   (32)
31 (30) Flowers subsessile; corolla pubescent inside.   17 S. loana
+ Flowers on pedicels 1-5 mm; corolla glabrous inside.   32 S. tomentosa
32 (30) Calyx and capsules glabrous or subglabrous; leaves 10-21 cm, with 15-19 pairs of secondary veins.   3 S. bifida
+ Calyx and capsules pubescent; leaves 1-25 cm, with 4-17 pairs of secondary veins   (33)
33 (32) Capsules villous; calyx lobes ca. 4 mm.   34 S. villosa
+ Capsules puberulent, pilosulous, pilose, or hispidulous; calyx lobes 0.3-1.5 mm   (34)
34 (33) Leaves 6.5-14 cm, with 11-17 pairs of secondary veins; corolla tube 7.5-9 mm.   8 S. corymbosa
+ Leaves 1-5 cm, with 4-9 pairs of secondary veins; corolla tube ca. 2 mm (only known in bud in S. microphylla)   (35)
35 (34) Leaves 1-3 × 0.5-4 cm, with 4-7 pairs of secondary veins; fruit with 4 valves.   24 S. microphylla
+ Leaves 3-5 × 1.5-3 cm, with ca. 9 pairs of secondary veins; fruit valves 2, sometimes tardily splitting into 4.   27 S. petrophila

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