Wilson and Johnson, Juncus (Juncaceae) in Malesia 
375 
Types: Japan: Yokohama, C. Mnximowicz, Iter Secundum; syn ?LE, ?W (n.v.). Nagasaki, 
C. Mnximowicz, Iter Secundum, 1863; syn K, L (2 sheets), ?LE, P, ?W (n.v.). Hakodate, 
C. Mnximowicz, Iter Secundum; syn ?LE, ?W (n.v.). Yokoska, P. Snvntier 1353, P, ?W (n.v.). 
A specimen of Maximowicz annotated by Buchenau should be chosen as lectotype 
since Buchenau clearly indicated in two places in the text that he considered the 
Savatier specimen to be intermediate between /. decipiens and ]. effusus sens, strict., that 
is, not typical. Duplicates of the Nagasaki collection, made in 1863 by Maximowicz, are 
held in L (L sheet 904,130-575 ex LE) and P but they are not annotated by Buchenau. 
Nakai's paper is written completely in Japanese (including page numbers) except for 
the title, photograph captions and plant names. It does not give any indication of 
basionym for /. decipiens Nakai, which is not surprising given that it is an ecological 
paper. The combination is valid despite this, since the rules about citing basionyms 
only apply from January 1953 (ICBN Article 33.2). 
[/. effusus auct. non L.: Backer 1951: 211] 
Shortly rhizomatous perennial. Culms terete, soft, mid-green, 20-120 cm long, 
l.l-2.2(-3.0) mm diam.; striations 20-50; pith continuous, very loose. Sterile leaf-like 
culms present but real leaves reduced to cataphylls 3-19 cm long, more or less tightly 
clasping the culm, abaxially pale straw-coloured above to darkish red-brown at least 
at base, shining towards base but more or less dull above, adaxially whitish with a 
pearly sheen. Inflorescence 2-9 cm long, diffuse, with numerous solitary flowers; 
lowest involucral bract 5-35 cm long, apparently continuous with culm, exceeding 
inflorescence. Flowers with 2 bracteoles. Tepals acuminate to acute, straw-coloured, 
often with a dark red-brown stripe on each side of midrib, with narrow to more or less 
broad hyaline margins; outer tepals 1.7-4.0(-4.5?) mm long, greater than or equalling 
inner tepals. Stamens 3, shorter than outer tepals; anthers 0.3-0.8 mm long, shorter 
than to exceeding filament length. Capsule 3-locular, slightly shorter than to slightly 
exceeding outer tepals, narrow-ellipsoid to ovoid or occasionally obovoid, golden 
brown to very dark red-brown, obtuse, not or scarcely beaked. Seeds 0.4-0.6 mm long. 
Distribution and habitat: In Malesia: in Peninsular Malaysia and on the islands of 
Sumatra (Aceh province), Java, Borneo (Sabah), Philippines (Luzon and Mindanao), 
and New Guinea. Also in eastern Asia: Japan, China, Taiwan, Korea, Thailand, and 
eastern India (Assam). Found in wet places, at higher altitudes in the tropical areas: in 
Malesia from 1400 to 3300 m. As pointed out by Hamet-Ahti (1980), this species does 
not occur in North America; what has been identified there as /. decipiens are slender 
collections of /. pylaei Laharpe. 
Notes: This species is similar to /. effusus sens, strict., with continuous, loose pith in the 
culms. It differs in having slightly more close-packed /dense pith than in J. effusus, and 
in being generally more slender than that species. Tire cataphylls have shining surfaces 
abaxially in /. decipiens, at least at the base and are adaxially whitish with a pearly 
sheen (dull abaxially, and adaxially golden to copper-coloured in /. effusus). /. decipiens 
has 20-50 striations around the circumference of the culms while /. effusus has 35-65 
striations. ]. decipiens differs from }. inflexus in having non-glaucous culms with 
continuous pith and more closely packed culm striations. 
Three intergrading subspecies are here recognised. The type subspecies is found in 
eastern Asia (eastern India, China, Korea, Japan, Thailand) and possibly in Peninsular 
Malaysia (one incomplete specimen seen), the other two are in other parts of Malesia 
(Philippines, Borneo, New Guinea, Java and Sumatra) and subsp. medinnus is also in 
Taiwan. The subspecies can be keyed out as follows: 
