Dioscorea pentaphylla L.

Tuber in some varieties elongated and burying deeply, in others not so and then globose or pyriform, in some cultigens palmately lobed, never stalked, generally coated if short by bristly roots, or if long with such roots on the upper part; flesh white or lemon yellow, sometimes with purple flecks in it, nauseous in the wild plants, though not particularly so if deep burying. Stem single, to 7 mm in diam. at the base, climbing to 10 m, and usually abundantly prickly over the lowest internodes, pubescent, but then glabrescent. Bulbils plentiful, globose or shortly ellipsoid, rarely cylindrical, skin brown, flesh yellow. Leaves 3-5-foliolate; petiole shorter than the middle leaflet by about ¼, pubescence deep rusty red or dirty white; middle leaflet broadly oblanceolate or obovate, apex shortly acuminate, not glandular, base obtuse or rounded, to 15 by 4½ cm; outer leaflets inequilateral with one additional primary nerve outside the midrib; leaflets relatively broader when 3 than when 5, pubescent on both surfaces, but soon glabrescent above. Petiolules at most 5 mm. Male flowering axes for the most part gathered on leafless branches of considerable size, only rarely axillary; axis to 3 cm long, carrying upwards of 50 flowers placed close together or in contact. Buds appearing to be globose because the bract and bracteole so wrap them as to hide their flat base. Pedicels ½-1 mm; bract and bracteole near the apex. Bracts usually broader than long. Outer tepals broadly lanceolate, subacute, pubescent or glabrous at the back, to 1(-1½) mm long; inner ones rather broader and blunter, glabrous. Stamens inserted at the base of the tepals, the 3 fertile stamens shorter than the staminodes; anthers twice as long as the filament. Female flowering axes directed downwards, 1-3 together from a leaf-axil, up to 25 cm long, pubescent, the hairs variable in the intensity of their redness. Tepals as in the male plant. Flower inverted after pollination. Capsule blackening somewhat as it ripens, with rounded shoulders about the apex though just retuse at the flower, base usually rounded; wings to 20 by 6 mm, retaining some pubescence until of full size.

A tropical plant. They grow from sea level up to 1600 m. It needs a well drained, well aerated soil. They are best adapted to an abundant rainfall during the growing season and an annual dry season. Soils need to be fertile. Five leaflet yam or Dioscorea pentaphylla L. occurs mainly in China; Malaysia; India; Indonesia; the Philippines; Papua New Guinea and into the Pacific Islands. It is common and widely distributed throughout the Philippines. In Yunnan.

Econ. It has been said that the jungle tribes of the Malay Peninsula seek it more than any other Dioscorea ( SKEAT & BLAGDEN Pagan Races 1 1906 109 ); but this seems doubtful as the supplies are small. The high forest shuts it out, and perpetual humidity is unfavourable. To lesser humidity is apparently due a greater abundance N of Penang and in the country behind Malacca. In both parts it is planted in garden fences whence tubers may be dug if required. The variety used is var. malaica PRAIN & BURK. ( PRAIN & BURK. J. As. Soc. Beng. new ser. 1 1914 23 ): rather long tubers, the middle leaflet is c. 4 times as long as broad. The Sakai call it jabet or chabet. Plants of N. Borneo may equally be referred to var. malaica.In a similar way D. pentaphylla is planted in garden hedges in other parts of Malaysia, in several varieties. OCHSE ( OCHSE Veget. D.E.I. 1931 255 ) has given an account of those in Java, describing the tubers of the most usual form as small, cylindrical and unbranched, calling it huwi sawut (fibrous yam). With it are more ennobled plants as huwijahe (ginger yam, so named from the shape), which is var. javanica BURK. ( BURK. Gard. Bull. Str. Settl. 3 1924 258 ).Huwi sawut can bear no botanical name at present because the Sundanese and the Javanese do not apply the vernacular name strictly. It occurs in bamboo thickets, on forest margins and in similar places, as well as in garden hedges; in the hedges it has encouragement without cultivation and now and then is dug for food, eaten roast or boiled by itself or in mixed vegetables as a flavouring.Superior to huwijahe and considerably superior to the average huwi sawut is var. sacerdotalis BURK. ( BURK. Gard. Bull. Str. Settl. 3 1924 258 ). It has high sounding names as huwi mantri (priest's yam), huwi putri (princess' yam) and huwi dewata (sacred yam); it has been suggested that they came to denote it because it was a food allowed on Hindu fast days. The foliage of these Javanese economic varieties is smaller than that of var. malaica and the male flowers are small in a degree which makes recognition easy, not of the exact variety for that depends on the tuber, but that one of the group is under the eye.var. sacerdotalis is recorded from the Res. of Madiun, Pasuruan and Besuki in E. Java and the Kangean Isl. between 1 and c. 1000 m. Its leaflets are broader, in proportion to their length, than those of the wider spread var. javanica BURK. ( BURK. Gard. Bull. Str. Settl. 3 1924 258 ) and not uncommonly there are simple leaves towards the stem-ends. The type was cultivated by K. HEYNE at Bogor, but he did not record whence he obtained it.var. javanica occurs in Celebes as well as in Java, and would seem to occur through the Lesser Sunda Islands. RUMPHIUS'S account of D. pentaphylla is interesting ( RUMPHIUS Herb. Amb. 5 1947 359 ): he wrote in particular of its uses in Sumbawa, where three kinds occurred. The first he called the white kind; it produced large white-fleshed tubers of which the extremities could be eaten although of vile flavour; the second he called the red kind and it had hard red flesh; it produced smaller tubers and they were better to eat; the third, called the black kind, turned black in cooking and blackened the water in which it was boiled. These cannot as yet be assigned to varietal names.The Ambonese, RUMPHIUS recorded, would transplant tubers from the forest to their gardens but not much and they would eat the produce of their gardens but not the plant direct from the forest unless driven by famine. The two tubers figured by him (pl. 177), the one lobed, the other clavate, represent respectively the cultivated and the wild plant.The above references do not dispose entirely of the forms of the species in SE. Malaysia, for FOR-STEN collected in Bima (Sumbawa Island) a very graceful plant which has not been seen from elsewhere.In the Philippines there are at least two varieties: one may be refered to var. malaica BURK., the other has been named var. palmata BURK. ( BURK. Gard. Bull. Str. Settl. 3 1924 258 ); it is a cultigen close to var. sacerdotalis, but larger in tuber. A plant appearing to be var. palmata has been collected in Timor.In New Guinea there is a very robust var. papuana BURK. ( BURK. Gard. Bull. Str. Settl. 3 1924 258 ) with a remarkably prickly stem up to 12 mm in diam. and so large as to have paired scale-leaves at the base. Can it be D. globifera R. KNUTH which otherwise remains unplaced?

They are grown from tubers or pieces of tubers. They can be grown from aerial tubers. The dormancy of the tuber can be short. They need stakes for support. Stakes of about 2 m are adequate although live stakes are often used. They often grow wild.