Spirodela polyrhiza

Content

Description

Ovary with 1 amphitropous ovule or 2 anatropous ones. Fruit a 1-2 seeded utricle, slightly winged. Seed smooth.

Distribution

Africa present, Almost cosmopolitan present, Asia-Tropical: Malaya (Peninsular Malaysia present); New Guinea present; Philippines (Philippines present); Sumatera (Sumatera present), Australasia, Flores Sea present, Hawaian Is.i present, Luzon present, Mindanao present, N. Celebes present, South America present, Tanah Djampea, S of Celebes present, W.-E. Java present, northern hemisphere present

Almost cosmopolitan, common in the northern hemisphere, rather rare in Africa and Australia, in South America replaced by two closely related species; in Malesia common: Sumatra, Malay Peninsula, W.-E. Java, Flores Sea (Tanah Djampea, S of Celebes), N. Celebes, Philippines (Luzon to Mindanao), New Guinea. Also in the Hawaian Is.i (1895 HELLER; 1927 LE ROY TOPPING), together with Lemna perpusilla.

Notes

Like many other Lemnaceae this species often forms resting-buds to survive less favourable times. In S. polyrhiza these resting-buds are easier to distinguish from the normal fronds than in the other Lemnaceous species and are often called 'turions'. They are produced in the normal way in the budding pouch. The turion is reniform, dorso-ventrally flattened, variable in size, consisting of dense tissue. Its roots are still present but when dormant only the primary roots are visible. On both sides it bears a membranous scale as does a normal young frond.

Citation

NUTTALL 1818 – In: Gen. Amer.: 19

HEGELM. 1868: Lemnac: 151-152

MASAMUNE 1943: Fl. Kainantensis: 394

KURZ 1866: pp. 267-268. – In: J. Linn. Soc. Lond.

Ridl. 1907 – In: Mat. Fl. Mal. Pen.: 53

BACK. & BAKH.f. 1968 – In: Fl. Java: 127

GRIFF. 1851 – In: Not.: 216

DAUBS 1965: Monogr. Lemnac: 10-13

WRIGHT 1903 – In: J. Linn. Soc. Bot.: 188

SCHLEID. 1871 – In: Bot. Zeit.: 621, 645

Hook.f. 1893 – In: Fl. Br. Ind.: 557

THOMPSON 1897 – In: Rep. Mo. Bot. Gard.: 27

MITRA 1958 – In: Fl. Pl. E. India: 86

TRIM. 1898 – In: Handb. Fl. Ceyl.: 367

CLARK & THIERET 1968 – In: Mich. Botanist: 69

BACK. 1924 – In: Handb. Fl. Java: 1

PRAIN 1903 – In: Bengal Pl.: 841

GAGNEP. 1942 – In: Fl. Gén. I.-C.: 1198

ZOLL. 1845 – In: Nat. Geneesk. Arch. N. I.: 212

NAVES 1882: Novis. App.: 296

Ridl. 1923 – In: J. Mal. Br. R. As. Soc.: 106

JUMELLE 1937: pp. 3-4. – In: Humbert, Fl. Madag. fam. 32

HUNDLEY & U CHIT Ko Ko 1961: List trees etc. Burma, ed. 3: 292

Merr. 1912: Fl. Manila: 134

MCCANN 1942: pp. 156-157. – In: J. Bomb. Nat. Hist. Soc.

Ridl. 1900 – In: J. Str. Br. R. As. Soc.: 179

COLLETT 1902: Fl. Simlensis: 545

HAND.-MAZZ. 1936 – In: Symb. Sin.: 1368

1851 – In: Ic. Pl. As.: t. 264

HEGELM. 1895 – In: Bot. Jahrb.: 284

HESS, LANDOLT & HIRZEL 1967 – In: Fl. Schweiz: 497

F. M. BAILEY 1914 – In: Queensl. Agric. J.: 78

LINNÉ 1925 – In: Fl. Mal. Pen.: 132

HEND. 1928 – In: Gard. Bull. S. S.: 352

LARSEN 1962 – In: Dansk Bot. Ark.: 136

BROWN 1901 – In: Fl. Trop. Afr.: 201

Roxb. 1832 – In: Fl. Ind., ed. Carey: 565

Benth. 1878 – In: Fl. Austr.: 164

FRANCH. & SAV. 1879 – In: En. Pl. Jap.: 13

SCHLEID. 1957: pp. 92-93. – In: Sc. Rep. Kanazawa Univ.

HASSK. 1847 – In: Flora: 469

Miq. 1855 – In: Fl. Ind. Bat.: 222

HARTOG & PLAS 1970 – In: Blumea: 360

SCHLEID. 1928 – In: Onkruidfl. Jav. Suikerr.: 175

STEEN. 1932: Arch. f. Hydrobiol.: 292

FISCHER 1931 – In: Gamble, Fl. Madras 3: 1593

KURZ 1864 – In: Nat. Tijd. N. I.: 220

SCHLEID. 1923 – In: En. Philip.: 190

OHWI 1965: Fl. Japan: 264

USTERI 1905 – In: Vierteljahrschr. Naturf. Ges. Zurich: 453