Flora of the Southeastern United States
2022 Edition


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Juncus Linnaeus. Rush.

Contributed by B.A. Sorrie and W.M. Knapp

Key to Juncus

A genus of about 250-300 species, herbs, of cosmopolitan distribution.

subgenus Juncus, section Juncus: acutus ssp. leopoldii, roemerianus
subgenus Juncus, section Graminifolii: biflorus, filipendulus, longii, marginatus, repens
subgenus Juncus, section Iridifolii: polycephalos
subgenus Juncus, section Ozophyllum: acuminatus, brachycephalus, brevicaudatus, caesariensis, canadensis, megacephalus, militaris, nodosus, paludosus, pelocarpus, subcaudatus, torreyi, trigonocarpus, validus
subgenus Agathryon, section Tenageia: bufonius, ranarius
subgenus Agathryon, section Steirochloa: anthelatus, brachyphyllus, coriaceus, dichotomus, dudleyi, georgianus, gerardi, interior, secundus, tenuis,
subgenus Agathryon, section Juncotypus: balticus, filiformis, effusus ssp. effusus, effusus ssp. solutus, gymnocarpus, inflexus, pylaei

ID notes: For identification of most rushes, it is important to collect plants with mature capsules and seeds. Stamen number is often a diagnostic character and can be determined after anthesis by counting the number of persistent filaments located behind the tepals. Care must be taken to collect specimens with uninjured heads, especially for the group of rushes in Key D; the long beaks of the capsules are often fragile and easily broken off.

Ref: Balslev In Kubitzki (1998b); Bridges & Orzell (2008); Brooks & Clemants (2000b) In Flora of North America Editorial Committee (2000); Clemants (1990); Hämet-Ahti (1980); Kirschner (2002b); Kirschner (2002c); Knapp (2014); Knapp (2016) In Naczi & collaborators (2019); Knapp & Naczi (2008); Záveská Drábková et al. (2003); Zika (2003); Zika (2013). Show full citations.

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