keys to the vascular plants of east texas - Botanical Research ...

ERIOCAULON/ERIOCAULACEAE 657
1. Petioles usually pubescent at junction with leaf blade, usually 7 cm or more long on well-developed
leaves; leaves in whorls of 4–7 at 1 or more lower nodes; rhizomes neither smooth nor
straight (contorted and with many knobs or short side branches), 10–15 mm in diam.; fresh
stems � round in cross section _____________________________________________________ D. quaternata
1. Petioles glabrous at junction with leaf blade, usually 6 cm or less long on well-developed leaves;
leaves of lower nodes at most opposite or with 3 in close proximity; rhizomes relatively smooth
and straight (knobs or side branches few or none), 5–10 mm in diam.; fresh stems polygonal in
cross section (with 8–14 angles) ________________________________________________________ D. villosa
ERIOCAULACEAE P. Beauv ex Desv. PIPEWORT FAMILY
Small, scapose, monoecious (usually) or dioecious, biennial or perennial herbs; leaves in a rosette,
crowded, spirally arranged, linear and grass-like in appearance, often long-tapering; inflorescence
a compact (2–20 mm broad), often whitish head solitary at the end of an elongate,
naked, angled scape, the scape with a basal sheath; heads composed of involucral bracts and
numerous unisexual flowers, the flowers each subtended by 1(–2) scarious receptacular bracts;
flowers small, with chaffy perianth parts; perianth parts and bracts often with clavate, multicellular,
often conspicuous, sometimes whitish hairs; sepals 2–3, distinct or fused; petals 2–3 or
reduced or absent; stamens 2–6; gynoecium of 2–3 carpels; ovary superior, on a gynophore, 2–3
locular, each locule with a single ovule; fruit a thin-walled loculicidal capsule.
AThe Eriocaulaceae is a medium-large (1,200+ species in ca. 13 genera—Kral 2000b) family of
usually perennial, small, scapose herbs distributed mainly in the tropics and warm areas, especially
in the Americas; a few are in temperate regions. Most species grow in full sun in wet
acidic soils or in aquatic situations (Kral 2000b). Because of the involucrate heads of many
small flowers, the Eriocaulaceae are sometimes referred to as the “Compositae of the monocots”
(Judd et al. 1999). This distinctive monophyletic family (Judd et al. 1999) seems to have a close
relationship with Xyridaceae (Linder & Kellogg 1995; Stützel 1998; Givnish et al. 1999). The following
treatment is modified from those by Kral (1966b, 1979b, 2000b). (subclass
Commelinidae—Cronquist; order Poales—APG II)
FAMILY RECOGNITION IN THE FIELD: wet area herbs with a basal rosette of linear, grass-like leaves;
flowers small and inconspicuous, in a small (2–20 mm in diam.) compact head at the end of an
elongate naked scape, the head often with a whitish appearance.
REFERENCES: Moldenke 1937, 1961; Kral 1966b, 1979b, 1989, 2000b; Dahlgren et al. 1985; Stützel
1998; Giulietti et al. 2000.
1. Roots (larger ones) thickened, pale, septate, appearing unbranched; lacunar tissue (= air spaces)
in the leaves evident to the naked eye; scapes glabrous AND heads 3–20 mm broad; perianth
parts in 2s, the sepals separate or united into a spathe, the petals united for most of their length
into a corolla tube which is 2-lobed above, each lobe adaxially bearing a jet black gland; heads
3–20 mm broad; stamens (3–)4(–6), the ripe anther surfaces of all native species black; carpels 2,
the style 2-branched, the gynoecium on a conspicuous gynophore _________________________ Eriocaulon
1. Roots fibrous and evidently branched; lacunar tissue in the leaves not evident to the naked eye;
scapes EITHER sparsely to densely hairy OR heads very small (2–3.5 mm broad); perianth parts
usually in 3s, the sepals separate, the petals absent or reduced to small eglandular hairs or scales;
heads 2–7(–9) mm broad; stamens 2 or 3, the anthers yellowish or pale; carpels 2 or 3, the style
2- or 3-branched (the branches bifid), the gynophore conspicuous or inconspicuous ________ Lachnocaulon
ERIOCAULON L. PIPEWORT, BUTTON-RODS, HAT-PINS
Clump-forming, usually monoecious, perennial or biennial (except sometimes annual in E.
kornickianum) herbs reproducing vegetatively by lateral offshoots or rhizomes; leaves � all in