水竹葉

Aneilema triquetrum Wall., Cat. 5220. 1832, nom. illegit; C. B. Clarke in DC., Monogr. Phanerog. 3: 208. 1881; Aneilema keisak Hassk., Commel. Ind. 32. 1870; C. B. Clarke in DC., Monogr. Phanerog. 3: 209. 1881. Murdannia triquetra (Wall.) Brückn. in Engl. et Prantl, Nat. Pflanzenfam. ed. 2, 15a: 173. 1930; D. Y. Hong, Acta Phytotax. Sin. 12 (4): 469, 1974; D. Y. Hong et al., Fl. Reipubl. Popularis Sin. 13 (3): 96. pl 25. 1997.

Annual aquatic herbs. Roots fibrous. Stems prostrate at base, erect above, branched, puberulent along a line decurrent from the sheath, otherwise nearly glabrous; rooting at nodes; internodes 1.2-4.1 cm long. Leaves sessile, blade linear to lanceolate, 2-6.7 cm long, 4-7 mm wide, apex acuminate, glabrous, scabrescent at margins, sheath puberulent at margins. Prophyll sheathing, 3-4 mm long, apex bifid or acute, glabrous. Inflorescence terminal, consisting of single flowers; 1-2 flowering shoots from axils of the cauline leaves; bracteoles lanceolate, 0.3-1 cm long; pedicels 0.6-1.6 cm long. Flowers actinomorphic; sepals lanceolate, boat-shaped, greenish, equal, ca. 4-7 mm long, ca. 1.5 mm wide, apex obtuse, glabrous or ciliate at apex; petals suborbicular, ca. 6-7 mm long, ca. 5 mm wide, white-purple or white, middle convexe, veins obscure in fresh material; fertile stamens 3, equal, antesepalous, anthers purple, narrowly elliptic-oblong, ca.2.5 mm long; pollen whitish; filaments ca. 3.5 mm long, bearded, the hairs moniliform, hyaline, on the outside of the filament; staminodes 3, equal, antepetalous, antherodes cordate, purple, ca. 0.75 mm long, filaments ca. 2 mm long, bearded, hyaline; ovary oblong-ellipsoid in outline, acutely 3-angled, ca. 1.75 mm long; style thickened toward the base, ca. 2 mm long, glabrous. Capsule trilocular, 3-valved, ellipsoid, 3-angled, 5.5-9.5 mm long, locules 2-3 seeded, apex mucronulate or acuminate. Seed brown, dimorphic: seeds in the end of the capsule deltoid in outline, others trapezoidal, 1-2.7 mm long, 1.2-1.5 mm wide, dorsiventral, ventral surface planar, dorsal convex, marbled, embryotega lateral or semilateral, sunken, hilum linear. Chromosome number: n = 20.

Taipei: Chihsingshan, on paddy field, Hsu 172 (TAI); between Kungliao and Hutzupei (a stone tablet), en route from Kungliao to Tali (Ilan Hsien), elev. ca. 200 m, Peng et al. 13579 (HAST); Hsintien: Tachichiao, along ridges of rice paddy, Chaw & Kao 239 (HAST); Oyayubi, Suzuki s. n. Nov. 6, 1932 (TAI); Pinglin District: Jenlipan, along River Chinkualiaohsi, elev. ca. 150-200 m, Peng et al. 10587 (HAST); Pinglin, Yang 1489 (TAI); same loc., Simizu 491 (TAI); Shihting, elev. ca. 150-500 m, Tateishi et al. 16636 (TAI); Shihting District: en route to Mt. Huangtitienshan, elev. ca. 440 m, Peng 8565 (HAST); same loc., Peng 5035 (HAST); Shihting District: Leikungpo, Hsiaoketou, elev. ca. 350-450 m , Peng & Hu 12279 (HAST); Wantan, Simizu 3222 (TAI); Wulai Hsiang: Fushan Village. Fushan Botanical Garden. Partly cleared and disturbed broadleaf forest, pond margin, elev. ca. 650 m, Peng et al. 15150 (HAST); Yangmingshan National Park: Datun Natural Park, elev. ca. 700 m Moist place, Wang & Liao 599 (HAST); Yonankuosiao, Kao 10161 (TAI). Taoyuan: Fuhsing District: en route from Hsiayun to Hsiayunping. Roadside and roadside slopes, elev. ca. 300-350 m, Peng 10272,10300 (HAST); Pachangli, elev. ca. 50-150 m, Peng 11129 (HAST); Yangmei: west of Puhsin, elev. ca. 50-150 m, Peng 11120 (HAST). Nantou: inter Gojio et Rengechi, Maw & Mori s. n. Nov. 2, 1932 (TAI); Gyochi, Yamamoto s. n. Oct. 22, 1929 (TAI); Mukaiyama-Rinryu, Kudo & Sasaki s. n. Sep. 23, 1929 (TAI); in aquis laci Nichigetsutan, prope Bokkitsu, Kudo & Sasaki 15314 (TAI); en route from Puli to Huisun Exp. Forest. Lu 25247 (TAIF). Pingtung: Ako, Matuda 681 (TAI). Ilan: Yuanshan Hsiang: Shuanglienpei (pound.), elev. ca. 550 m, Y. J. Chen et al. 893 (TNU).

Northeastern USA, Southeastern USA, Italy, Japan, Korea, India, Vietnam, Laos, Cambodia, China (Shandong, Henan, Shanxi, Sichuan, Guizhou, Yunnan, Guangxi, Hainan, Guangdong, Hunan, Hubei, Jiangxi, Anhui, Jiangsu, Zhejiang, Fujian). Taiwan, usually found in swamps, marshes, and rice fields. Flowering in Jul.- Jan., central in Sep.- Nov.

依據Clarke (1881) 及Hong (1997) 描述M. keisak及M. triquetra為極類似的兩個分類群︰ 1. Clarke (1881) 描述M. triquetra果實每室有種子3-5顆，蒴果長5 mm，寬2-2.5 mm；M. keisak果實每室有種子4-6顆，蒴果長8 mm，寬3-4 mm，種子大而扁。 2. Hong (1997) 描述M. triquetra蒴果長圓狀三棱形，兩端稍鈍，種子不扁，萼片長4-6 mm；M. keisak蒴果長橢圓形，不明顯三棱，兩端急尖，種子扁，萼片長6-10 mm。 本研究觀察台灣的族群，發現各族群間形態極為類似，省產本分類群之蒴果從長圓狀三棱形至長橢圓形皆有，蒴果每室2-3顆種子，種子扁，大小不一，要視種子發育情形而定，萼片長4-7 mm，許多特徵皆介於M. triquetra及M. keisak之間，因此認為兩者應指同一個分類群。 A. triquetra直到C. B. Clarke (1881) 才為有效的發表，故應採用 M. keisak。 本分類群為一年生的水生植物，可孕雄蕊花藥長2.5 mm，退化雄蕊花藥紫色且為心型，單生花，這些特徵明顯異於省產同屬的其他種類。另外，Murdannia屬植物大都具有兩性花及雄花二種形態的花，但本研究觀察此分類群並沒有發現功能性的雄花。

Phenology: perennial herbs, evergreen, aquatic

Roors form: roots fibrous

Stems form: monomorphic stem

Monomorphic stems habit: procumbent

Rooting at nodes or not: rooting at nodes

Lateral shoots: not perforating

Phyllotaxis: spiral phyllotaxis

Leaves: petiole: sessile

Leaves: shape (if dimorphic leaves, selected by rosette leaves): lanceolate, linear

Leaves: apex: acuminate

Leaves: length (cm): 2-6.7

Leaves: width (cm): 4-7

Leaves indumentum: upper surface: glabrous

If upper surface glabrous, leaves indumentum: margin: pubscent

Prophyll: sheathing, apex acute, sheathing, apex bifid

Inflorescence: take plance: terminal

Inflorescence: solitary

Bracts: shape: lanceolate

Corolla: actinomorphic: petal 3, base free, equal or subequal

Flowers: bisexual

Sepals: sepal 3, equal

Sepals: color: greenish

Sepals: base: free

Sepals: shape: lanceolate

Sepals: indumentum: glabrous

Sepals: length (if dimorphic sepals, selected by anticous two) (mm): 4-7

Sepals: width (if dimorphic sepals, selected by anticous two) (mm): 1.5

Flowers: color: pink, purple, or blue

Petals: shape: suborbicular

Petals: length (mm): 6-7

Petals: width (mm): 5

Stamens form: dimorphic: fertile stamens 3

Ovarys: shape: oblong-ellipsoid

Ovarys: indumentum: glabrous

Ovarys: length (mm): 1.75

Styles: indumentum: glabrous

Styles: length (mm): 2

Capsules: dehiscence: dehiscent

Capsules: shape: ellipsoid

Capsules: trilocular

Capsules: indumentum: glabrous

Capsule locules seeds: number: 2-3

Capsules: length (mm): 5.5-9.5

Seeds: lengh (if dimorphic seeds, selected by dorsal one) (mm): 1-2.7

Seeds: width (if dimorphic seeds, selected by dorsal one) (mm): 1.2-1.5