258 USEFUL PLANTS OK (JUAM. 



( tiictliiiif: is ci'i-taiii, tlio spiny wilil yam calk-d "fj;a(lo" or "nikaciinarroii," wliiih 

 forms (li'iisc tliicki'ts in tlio forests of (iuam and f\irnishes the natives with food in 

 the periods nf famine wiiieh fcjllow imrricanes, is not tiie Dioscorea acaleata ot Lin- 

 naeus, as was supposed l)y Gaudiehaud. />. (u-nlidhi L. is very probal)iy tlie species 

 deserilied under tiiat name hy Seemann, a plant cultivated by the Fijians, in the 

 description of which Seemann does not mention l)ranching sharp spiny jjrocesses 

 about the base of the stem, such as characterize the spiny yam of this island and 

 which are features of the Dioscorea aculeata ol Roxburgh/' According to Hooker, 

 Roxburgh's Dioxrorm (tculmUi is identical with /). xp'mosa Roxb.,^ the description 

 of which ct)rresponds to our yado. 



The typical nika of Guam resembles I), aniledln L., and corresponds very closely 

 witii />. /a«'/cu/rt/o Zit^escerjs, as described by Padre Blanco, c Some of the varieties 

 seem identical with D. ixtpnana Warb. 



In the list of yams given by Schumann and Lauterbach as occurring in the Bismark 

 Archipelago and Kaiser Wilhelmsland, on the coast of New Guinea, are Dioscorea 

 glabra Roxb. ; />. papuana Warb., perhaps the most extensively cultivated species; 

 D. pi'iifaphyUa L., growing on the edge of the forests; D. mtiva L., w^hich "produces 

 great tul)ers," growing in the woods, occurring also, according to Finsch, in Ponape, 

 Kuschai, and Ualan, of the Caroline Group; and D. alata, which is cultivated.'^ 



According to Hooker, a part of Linnaeus' description of Dioscorea saliva ^ applies to 

 D. spinosa Roxb., to which should also be referred D. aculeata Roxb., D. tiliaefolia 

 Kunth, and D. lanata Balf. Linn;ieus' true D. saliva is a glabrous plant, the stem 

 terete, bulbiferous, the leaves broadly ovate-cordate, acuminate, cuspidate; and to it 

 should be referred D. hulhifera R. Br..^' D. glabra is quite glabrous, with very variable, 

 long-petioled, opposite, caudate-acuminate leaves, the youngest acute at the base, 

 the older truncate or deeply cordate, the lobes sometimes 2.5 cm. long, incurved 

 and overlapping, orbicular, ovate-oblong, or hastate, strongly 7 to 9-nerved, and 

 reticulate, subglaucous beneath. In the face of so many conflicting authorities it 

 is hard to decide as to the species or recognized varieties cultivated in Guam. A 

 thorough study of the yams of this island is especially desirable, since most of the 

 varieties were cultivated by the natives before the discovery.? 



The species of Dioscorea can not be understood from herbarium specimens alone. 

 The food-yielding varieties must be studied in the localities where they are cultivated, 

 and should be represented in herbaria by photographs of the growing plants, together 

 with their tubers, and, if possible, by typical tubers of each variety preserved in 

 formalin or some other liquid. It is only in this way that specimens from Polynesia, 

 India, the Malay Archipelago, Africa, Australia, and America can be compared. 



Plants belonging to the genus Dioscorea are herbaceous perennials with fleshy 

 tuberous roots and twining stems, which, as a rule, die down each year, allowing 

 the plant to rest through the dry season. Leaves having several longitudinal veins, 

 either entire, lobed, or digitately 3 to. 5 foliolate, the petiole often angular and 

 twisted at the base. Flowers small or minute, panicled, racemose, or spicate, rarely 

 bisexual, the perianth superior, 6-cleft. Male flowers with the perianth tubular or 

 urn-shaped, its lobes shortly spreading. Stamens inserted at the base of the perianth 

 or on its lobes, 3 or 6, or 3 perfect stamens and 3 staminodes, the filaments incurved 

 or recurved, the anthers small, globose, oblong or didymous, or with the cells on 



« Flora Indica, vol. 3, p. 800, 1832. 



6 Ex Wallich, Catalogue, No. 5703, A, B, C, D, E, F. 



f Flora de Filii)inas, ed. gran, vol. 4, p. 260, 1880. 



rf Schumann und Lauterbach, Flora deutschen Schutzgebiete, pp. 223-224, 190J. 



« Species Plantarum, ed. 1, vol. 2, p. 1033, 1753. 



/Prodromus Flora Novfe HoUandijc, p. 294, 1810. 



f/One of the first Jesuit missionaries to visit the island was killed by a native in 

 coiisequence of a misunderstanding over some "nika" roots which the native failed 

 to <leliver as he had promised. 



