Q5R USEFUL PLANTS OF GUAM. 
One thing is certain, the spiny wild yam called “ gado”’ or ‘‘nikacimarron,’’ which 
forms dense thickets in the forests of Guam and furnishes the natives with food in 
the periods of famine which follow hurricanes, is not the Dioscorea aculeata of Lin- 
naeus, as was supposed by Gaudichaud. 7). aculeata L. is very probably the species 
described under that name by Seemann, a plant cultivated by the Fijians, in the 
description of which Seemann does not mention branching sharp spiny processes 
about the base of the stem, such as characterize the spiny yam of this island and 
which are features of the Dioscorea aculeata of Roxburgh.@ According to Hooker, 
Roxburgh’s Dioseorea aculeata is identical with D. spinosa Roxb.,® the description 
of which corresponds to our gado. 
The typical nika of Guam resembles D. aculeata L., and corresponds very closely 
with D. fasciculata lutescens, as described by Padre Blanco,¢ Some of the varieties 
seem identical with D. papuana 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.; D. papuana Warb., perhaps the most extensively cultivated species; 
D, pentaphylla L., growing on the edge of the forests; J). sativa L., which ‘* produces 
great tubers,’? growing in the woods, occurring also, according to Finsch, in Ponape, 
Kuschai, and Ualan, of the Caroline Group; and 2. a/ata, which is cultivated. 
According to Hooker, a part of Linnzeus’ description of Dioscorea sativa ¢ applies to 
D. spinosa Roxb., to which should also be referred D. aculeata Roxb., D. tiliaefolia 
Kunth, and D. lanata Balf. Linneeus’ true D. sativa is a glabrous plant, the stem 
terete, bulbiferous, the leaves broadly ovate-cordate, acuminate, cuspidate; and to it 
should be referred D. bulbifera R. Brot 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 {-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. 9 
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 orsome 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 vear, allowing 
the plant to rest through the dry season. Leaves having several longitudinal veins, 
either entire, lobed, or digitately 8 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. 
bx Wallich, Catalogue, No. 5708, A, B, C, D, EF, F. 
‘Flora de Filipinas, ed. gran, vol. 4, p. 260, 1880. 
@Schumann und Lauterbach, Flora deutschen Schutzgebiete, pp. 223-224, 1901. 
€Species Plantarum, ed. 1, vol. 2, p. 1033, 1753. 
fProdromus Flora Noyes Hollandia, p. 294, 1810. 
gOne of the first Jesuit missionaries to visit the island was killed by a native in 
consequence of a misunderstanding over some ‘‘nika’’ roots which the native failed 
to deliver as he had promised, 
