Wilson and Johnson, Juncus (Juncaceae) in Malesia 
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/. prismatocarpus [var. leschenaultii] subvar. y thermalis Buchenau (Buchenau 1890: 312). 
Type citation: 'In den Saanschen heissen Quellen auf Kamschatka; gesammelt von 
Rieder.' Type: Kamchatka, J.G. von Rieder; syn ?E, ?FI, ?LE, ?W (n.v.). 
?]. yakeisidakensis Satake (Satake 1933: 189, fig. 21). Type citation: 'Honsyu: Mt 
Yakeisidake, prov. Rikutyu (H. hvabuchi, 1931 — type in Herb. Imperial Univ. Tokyo).' 
Type: Japan: Mt Yakeisidake, Honshu, H. hvabuchi, 1931; holo TI (n.v.). 
/. latior Satake (Satake 1936:90). Type citation: 'Honsyu: Prov. Sagami — circa Zimmuzi 
(Y. Momiyama, Jun. 6, 1929, no. 454 — Typus).' Type: Japan: Zimmuzi, Honshu, 
Y. Momiyama 454, 6 June 1929; holo TI? (n.v.); iso K. 
[/. prismatocarpus auct. non R. Br.: Backer 1951: 213 p.p.; Larsen 1972: 168; Van Royen 
1979: 815; Harriman 1991: 389; Noltie 1994: 254] 
Tufted perennial. Culms compressed to more or less terete, ?yellow-green, 8-15(-30) 
cm long, 0.7-1.5 mm diam. Leaves pluritubulose, spread along culms, shorter than to 
exceeding culms, compressed to more or less terete, acute to obtuse, 0.7-1.5 mm diam.; 
auricles to 0.5 mm long. Inflorescence terminal, 1-5 cm long, diffuse, with flowers 
clustered, 3—8[—20] per cluster and 3-9 clusters per inflorescence, often proliferating; 
1 well-developed involucral bract, 1.5-4 cm long, lateral, shorter than or equalling 
inflorescence. Flowers without bracteoles. Tepals acute to acuminate, the tips 
spreading to recurved at maturity, straw-brown to slightly red-tinged, with more or 
less broad hyaline margins; outer tepals 2.8-4.0(-4.5) mm long, more or less equalling 
inner tepals. Stamens 3 (rarely to 6), shorter than outer tepals; anthers 0.3-0.8 mm long, 
shorter than filaments. Capsule 1-locular, slightly exceeding (to 1 mm) or occasionally 
equalling outer tepals, very narrow-ellipsoid to narrow-ovoid, golden brown, acute to 
broad-acute, not or shortly beaked (to 0.2 mm long). Seeds 0.3-0.4 mm long. 
Illustrations: Fig. le, f; also Backer (1951: fig. 2a); Van Steenis (1972: pi. 24-2); Van 
Royen (1979: fig. 279); all as J. prismatocarpus. 
Distribution and habitat: In Malesia, in the Cameron Highlands of Peninsular 
Malaysia and on the islands of Sumatra (North and West), Java (West and Central), 
Philippines (Luzon and Mindanao) and New Guinea; also from India and Sri Lanka to 
China, Kamchatka and Japan. Adventive in Mauritius in one area (Coode 1978: 3). In 
Malesia, only at higher altitudes (1400-3200 m) in swamps and on stream banks. No 
collections have been seen from Mindanao, but Backer (1951) included this island in 
its distribution (as ]. prismatocarpus). According to Backer (1924: 44; Backer and 
Bakhuizen f. 1968:451 ),']. prismatocarpus' (that is, either J. leschenaultii or /. wallichianus 
or both, in this context) occurs on the mountains in West, Central and East Java. 
However, Backer (1951: 214) does not mention East Java for this 'taxon' and we have 
not seen specimens of either species from East Java. In fact, ]. wallichianus seems to be 
more common in Central Java than in West Java and vice versa for /. leschenaultii. 
The Cameron Highlands records are all relatively recent (1956 and later), but Kern 
(1958; as J. prismatocarpus) argues convincingly that the species is just as likely to be 
native there as introduced, surmising that the species has spread more widely there 
since the area has been cleared as a holiday area. This would be similar to the situation 
with many native Juncus species in Australasia, which seem to have spread much more 
widely thanks to human disturbance in the last two centuries (Johnson 1991). 
Notes: Plants may proliferate from the flowers, as seen also in /. wallichianus; this is 
illustrated by Van Royen (1979: fig. 279). This species has been confused in Malesia 
and elsewhere (see, e.g.. Backer 1951, Noltie 1994) with J. prismatocarpus, which is a 
more robust pluritubulose species that is confined to Australia and New Zealand. 
