Juncus guadeloupensis Buchenau & Urb.

  • Authority

    Balslev, Henrik. 1996. Juncaceae. Fl. Neotrop. Monogr. 68: 1-167. (Published by NYBG Press)

  • Family

    Juncaceae

  • Scientific Name

    Juncus guadeloupensis Buchenau & Urb.

  • Type

    Type. Guadeloupe. Headwaters of Glass River, 995-1200 m, 19 May 1899, Duss 3996 (lectotype, NY!, here selected; isotypes, AAU!, C!, F!, MO!, US!).

  • Description

    Species Description - Perennial herbs to 150 cm tall. Rhizome not seen. Culms erect, terete, smooth, up to 6 mm diam. Cataphylls 0-3 to each culm, inserted somewhat separated, to 10 cm long, margin scariose, apex rounded with rudimentary acicular to 4 mm long blade. Foliar leaves 3-7, evenly distributed along the culm, to 40 cm long; sheaths to 10 cm long, with a scariose margin terminating in two, 4 mm long, rounded auricles; blades 2-3(-4) mm diam., round in x.s., hollow with septa 1-3 cm apart. Inflorescence decompound, repeatedly anthelate, up to 25 x 15 cm when fully developed, flower heads 15-35, globose at maturity, to 15 mm diam., 10-30-flowered, principal branches 2-10 cm long and 0.5-1.5 mm diam. Lower inflorescence bract 26 cm long, much shorter than the inflorescence, resembling cauline leaves, distal bracts shorter, floral bracts about ½ as long as the flowers, scariose. Tepals equal, 3-4.5 mm long, linear-lanceolate, acuminate, pale green with varying amounts of red pigmentation, margins narrowly but distinctly scariose, outer tepals concave, at least at the base, inner tepals flat. Stamens 3, ca. 2.5 mm long or about 2/3 as long as the tepals, anthers oblong, 0.9-1 mm long, shorter than the filiform filaments. Capsule obclavate, acute, trigonous at the base, pyramidal at the apex, 4-6 x 1-1.5 mm, obviously exceeding the tepals at maturity, golden yellowish brown, unilocular. Seeds oblique, ellipsoid, short tailed, 1-1.1 x 0.3 mm, reticulate, yellowish brown below a hyaline outer seed coat.

  • Discussion

    Buchenau (1900, 1906) and Foumet (1978) cite “Juncus acuminatus Husnot & Coutance” as a synonym of J. guadeloupensis, but that name was never published by Husnot and Coutance, who merely misidentified a syntype of J. guadeloupensis (Husnot 46) as J. acuminatus Michaux (Husnot & Coutance, 1871).

    Howard (1979) designated “Duss 3996” as lectotype, but as a lectotype must be a specimen, not a collection, I have selected “Duss 3996 (NY)” as the lectotype.

    Distribution and Ecology: Endemic to Guadeloupe and possibly the island of Martinique (Lesser Antilles) at elevations of 1000-1200 m. Howard (1979) states that recent collections from the upper slopes of the Soufriere volcano on Guadeloupe dispel fears that this endemic species may have been endangered by recent eruptions. He found several populations in 1978 on Soufriere flowering prolifically, and plantlets had established themselves epiphytically on adjacent shrubs. This is the only report of epiphytic Juncaceae. Sastre (pers. comm., 1981) says that J. guadeloupensis is spreading along trails and on compacted soil at elevations of 1000-1300 m on Guadeloupe. Duss 4622 from Martinique, cited below, is a specimen of sterile septate-leaved Juncus, but a definite identification is not possible. In 1902 the “Lac des Palmistas” and the plant life around it was destroyed by a volcanic eruption, so the Martinique occurrence of J. guadeloupensis can presumably not be verified.

  • Distribution

    Guadeloupe South America| Martinique South America|