136 PHILIPPINE PALMS 
Key to the genera of Philippine palms. 
1. Leaves simple, fan-like. 
2. Leaves divided almost to base into 14 to 20 segments; stems tufted, 
small. 13. Licuala. 
2. Leaves not deeply divided; trunk stout, never tufted. 
3. Trunk smooth, with annular scars; inflorescences axillary, pen- 
dulous. 14. Livistona. 
3. Trunk without annular scars, often 60 centimeters or more in diam- 
eter; flowering-shoot terminating the trunk, the plant flowering once 
and then dying. 8. Corypha. 
1. Leaves bipinnate, leaflets cuneate at the base, rhomboid, oblique, the 
tips resembling the fins or tails of fish. 6. Caryota. 
1. Leaves pinnate. 
2. Climbing spiny palms; leafsheaths and midribs armed; fruit covered 
with scales, usually shiny. 
3. Leaflets rhomboid or wedge-shaped, whitish beneath; leafsheaths 
usually inflated and occupied by ant nests. 12. Korthalsia. 
3. Leaflets elongated, never rhomboid. 
4. Branches of the inflorescences covered with very large, broad, 
overlapping bracts concealing the flowers; the plant flowers once 
and then dies. 22. Plectocomia- 
4. Branches of the inflorescences only slightly expanded, bracts not 
concealing the flowers; the plant flowers many times. 
5. Spikelets in the axils of tubular or funnel-shaped spathels; flag- 
ellae from end of midrib or from the leafsheaths. 5. Calamus. 
5. Spikelets in the axils of large boat-shaped or open deciduous 
spathels; flagellae always from end of the midrib. 
9. Daemonorops. 
2. Not climbing. 
3. Tufted, spiny palms. 
4. Growing in fresh-water swamps, the inflorescences terminating - 
the tall, mature trunks; the sago palm. 15. Metroxylon. 
4. Growing on dry ground; stem short or none; inflorescence from 
base. Rare, known only from Lanao. 24. Zalacca. 
3. Stems creeping in the mud of salt-water swamps; trunks none; in- 
florescences on short, erect stalks from the rhizomes, the infruc- 
tescence a large globose head; the nipa palm. 16. Nipa. 
3. Erect, simple palms, the stems never tufted (except some species of 
Arenga), the infiorescences always lateral, never terminal. 
4. Inflorescences from the trunk at the base of the leafsheaths. 
5. Trunks covered with long, slender spines. 17. Oncosperma. 
5. Spineless palms. 
6. Trunks large, swollen in the middle; the royal palm, cul- 
tivated only. 19. Oreodoxa. 
6. Trunks small or of medium size. 
7. Female flowers few, at the base of the branches of the 
inflorescences, much larger than the much more numerous 
male ones. 3. Areca. 
7. Flowers of both sexes alike in shape and size, or flowers 
perfect. 
8. Flowers in groups of threes on the spike-like branches 
of the compound inflorescence. 2. Adonidia. 
