Page 327: Revision of Pandanus, 16. Thailand, Vietnam — S t. John 
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pressed; the midrib below with similar prickles 
1.7-2 mm long, 6-15 mm apart, ascending; near 
the apex the margins with subulate-tipped ap- 
pressed serrations 0. 1-0.3 mm long, 1-4 mm 
apart; those of the midrib below similar but 
0.2-0.6 mm long, 2.5-6 mm apart; peduncle 
terminal, 7-12 cm long, 3-4 mm in diameter, 
with many leafy bracts, the median ones 21 cm 
long, 8 mm wide, the upper ones 7 cm long, 17 
mm wide, foliaceous, white; syncarp single, 
pendent, elliptic-subglobose, 36-55 mm long, 
35-42 mm in diameter, bearing 230-592 
drupes, these 14-19 mm long, 4-4.2 mm wide, 
3 mm thick, narrowly oblanceoloid, 5-7 -angled, 
the sides gently curving, upper l A free; pileus 
conic, but when dry with longitudinal wrinkles, 
the base connate with adjacent ones, leaving no 
visible suture; style 2-3.5 mm long, stout su- 
bulate, pale, cartilaginous, curved upward to- 
wards apex of syncarp ( or the basal ones curved 
distally); stigma 1.5-2. 5 mm long, lanceolate, 
proximal, brown papillose; endocarp central, 6 
mm long, narrowly obovoid, cartilaginous, 
brown, shiny within, the walls 0.1 mm thick; 
apical and lateral mesocarps continuous, dry 
pithy; basal mesocarp fibrous and fleshy. 
STAMINATE PLANT: Stem 8 cm or a little 
more in height, 7-10 mm in diameter, dark 
brown, striate, shining; leaves numerous in 
terminal tuft, 46-48 cm long, just above the 
base 12-13 mm wide, at the middle 7-8 mm 
wide, green, secondary parallel veins prominent 
throughout and at midsection 14 in each half, 
the base amplexicaul, unarmed, softer, beginning 
3.5-4 cm up the margins with prickles 2. 3-3. 5 
mm long, 5-15 mm apart, arcuate, heavy subu- 
late, ascending, yellow; the nearby midrib below 
beginning at 5-5.5 cm with prickles 2-2.5 mm 
long, 6-15 mm apart, similar but reflexed, at 
the point of reversal of direction often paired; 
at midsection the margin and midrib below with 
similar prickles 1-2.5 mm long, 4-6 mm apart, 
ascending; staminate inflorescence terminal; pe- 
duncle 6 cm long, 1.5 mm in diameter, leafy 
bracted; floral part 11 cm long; lowest floral 
bract about 45 cm long, the base 15 mm wide, 
soft, white, veiny, unarmed, narrowly lanceolate, 
the upper part 6 mm wide, green, subcoriaceous, 
at midsection the margins with prickles 0.5-1 
mm long, 2-3 mm apart, arcuate subulate, as- 
cending, yellow; the midrib below with similar 
ones 0.3-0. 5 mm long, 1.5-3 mm apart; the 7 
spikes fragrant, 2.3-3 cm long, 6-8 mm in di- 
ameter, narrowly ellipsoid, densely flowered; 
stamens numerous, in fascicles; staminal column 
2-2.5 mm long, stout, but tapering upwards; 
free filament tips 0.5 mm long; anthers 0.7-0.8 
mm long, lanceolate, bearing on its apex a su- 
bulate projection of the connective 0.2 mm long. 
HOLOTYPUS: Thailand (Siam): Pii Wieng, 
Kawn Ken, by dry stream bed, 300 m. alt., Feb. 
7, 1931, A. F. G. Kerr 20,016 (bk). 
specimens EXAMINED: Thailand (Siam), 
Bung, Ubon, by stream in open forest, 100 m. 
alt., Jan. 29, 1924, A. F. G. Kerr 8,365 (bk); 
n. e. part, Loei, Phu Luang, by stream, 1,000 m. 
alt., 24 Sept. 1957, Dee Bun Pheng 914, stami- 
nate and pistillate (bkf no. 16,154). 
DISCUSSION: P. thailandicus is a member of 
the section Rykia, as is its closest relative, P. 
immersus Ridl. of Malaya, a species with the 
syncarp (immature) 9.5 cm long, 6 cm in di- 
ameter, ellipsoid, with about 1,440 drupes, these 
5-6 mm wide; pileus 7-8 mm long; style 4-6 
mm long; plant aquatic; leaves "many feet long," 
10.2 cm wide, caudate subulate apex 3.0. , cm 
long, at midsection with 70 secondary veins in 
each half, and the margins with prickles 2.5-4 
mm long, 9-18 mm apart. P. thailandicus has the 
syncarp 3.6-5. 5 cm long, 3. 5-4.2 cm in diame- 
ter, elliptic-subglobose, with 230-592 drupes, 
these 4-4.2 mm wide; pileus 3.5-6 mm long; 
style 2-3.5 mm long; plant terrestrial; leaves 
35-50 cm long, 6 - 10 mm wide, the subulate 
apex 7 cm long, at midsection with 13 veins in 
each half and the margins with prickles 1.3-1. 8 
mm long and 4-7 mm apart. 
The new epithet is geographic, referring to 
the native country of the species. 
Pandanus unicornutus sp. nov. (sect. Rykia) 
Fig. 204 
NOM. VERN.: "chawng 11”; "toi yai.” 
DIAGNOSIS HOLOTYPI: Arbor ad 8 m alta 
ramosa, foliis "ad 3.5 m. longis” 10-11 cm latis 
proxima basem crassiter coriaceis in apice subu- 
lato 8 cm longo abrupte contractis eo 10 cm ex 
apice 7 mm lato in sectio late M-formatis in 
puncto 30 cm ex basi cum 70 nervis secundariis 
in quoque latere, basi integra et amplexicauli sed 
ex 15 cm marginibus cum spinis 4.5-6 mm longis 
