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decumbent trillium, trailing wakerobin

brook trillium, brook wake-robin

Rhizomes

short, thick.

horizontal, short, praemorse, fleshy.

Scapes

1–2, decumbent, usually by an S-shaped curvature, round in cross section, 0.5–2 dm, somewhat stout, slightly expanded toward bracts, densely puberulent, especially just below bracts and on bases of main bract veins beneath.

1–2, round in cross section, 0.4–1.5 dm, slender, glabrous.

Bracts

appearing early in season, in good condition for only a few weeks after anthesis, dying back to semipersistent bases early, resting on ground surface, sessile;

blade strongly mottled in shades of green and bronze and with silvery overlay, mottling becoming obscure with age, ovate to suborbicular, 4–12 × 3.3–7 cm, apex acute to rounded.

distinctly petiolate;

blade bluish green, occasionally with silvery green pattern along major veins, ovate-lanceolate, 1.5–8 × 0.8–6 cm, somewhat thick-textured, glossy, weakly to strongly cordate basally, apex long-acuminate;

petiole (0.5–)1–3(–6) cm.

Flower

erect, odor unreported;

sepals divergent, green- or maroon-streaked, lanceolate-ovate, 22–48 × 9–14 mm, margins entire, flat, apex acute;

petals long-lasting, rigidly erect, ± connivent, ± concealing stamens and ovary, dark maroon-purple when fresh, fading especially distally to dull reddish brown, greenish brown, or with creamy yellow tones, very rarely pale lemon yellow forms occur, twisted (but not spiraled), linear-lanceolate or oblanceolate, 4–8+ × 0.7–1 cm, thick-textured, margins entire, apex acute;

stamens erect, straight, dark purple, 10–25 mm;

filaments dark purple, 2–5 mm;

anthers straight, dark purple, 9–20 mm, dehiscence extrorse;

connectives broad, extending to 3.5–4 mm beyond anther sacs;

ovary dark purple, oval, 6-angled, 5–10 mm;

stigmas erect, divergent-recurved, distinct, sessile, pink or white, subulate, 4.5–8 mm.

erect, rapidly recurving below bracts after pollination, ± odorless;

sepals conspicuous, spreading, green, weakly sulcate, oblong or tapered apically, usually shorter and narrower than petals, 10–23 × 4–8 mm, margins entire, apex rounded-apiculate;

petals erect-spreading, not recurved or only in distal 1/2, white (rarely pale pink), usually with dark madder-purple flecks, rarely almost entirely covered with madder-purple, color not changing with age, veins inconspicuous, not engraved, ovate-cordate to ± orbicular, tapered bluntly apically above middle, 1.3–2.8 × 1–2.4 cm, ± thin-textured, base rounded, cuneate, margins entire, mostly without undulations, apex ± apiculate-acuminate;

stamens erect, 5–12 mm;

filaments white, ± equaling anthers;

anthers straight, yellow, 3–6 mm, dehiscence ± extrorse;

connectives not extended beyond anther sacs;

ovary creamy white, ovoid, weakly 6-angled but angles in close pairs, giving superficial impression of 3-angled ovary, short, 3–9 × 4 mm, somewhat obscured by anthers broadly attached;

stigmas recurved and appearing ± lobed adaxially, at least in dried specimens, connate basally to distinct and closely grouped, white or cream, 2–4 mm, uniformly thick, fleshy;

pedicel strongly erect at anthesis, strongly recurving and elongating below bracts after pollination, 2.5–11 cm.

Fruits

baccate, dark purple, broadly ovoid to subglobose, crownlike, strongly ridged, 1–1.5 × 1 cm, pulpy but not juicy, present and enlarging on naked scapes until early autumn.

greenish white, odorless, globose, 0.9–1.2 × 0.8–1 cm, pulpy, not juicy.

2n

= 10.

= 10.

Trillium decumbens

Trillium rivale

Phenology Flowering late winter–spring (mid Mar–Apr). Flowering spring (early Mar–early Jun); withering in summer.
Habitat Thin, open rocky wooded slopes, mature deciduous woodlands, rocky talus and disintegrating shale, flats (floodplains) of small streams and adjacent slopes near river entrance Open, grassy hillsides, manzanita shrubbery, pine groves, clearings in sequoia groves, roadside banks, ledges, gravelly talus
Elevation 50–200 m (200–700 ft) 10–1400 m (0–4600 ft)
Distribution
from FNA
AL; GA; TN
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; OR
[WildflowerSearch map]
Discussion

Trillium decumbens occurs in the Ridge and Valley and Cumberland Plateau physiographic provinces. It has a large, deep, horizontal rhizome, the growing point of which always faces downslope.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Trillium rivale is confined to the Klamath and Siskiyou mountains of southwestern Oregon and California. It has a strong affinity for banks along streams and adjacent to trickles in Darlingtonia bogs, mainly on serpentine soils. After flowering, the entire plant may enlarge and become more robust and turgid with very glossy leaves.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 26, p. 109. FNA vol. 26, p. 102.
Parent taxa Liliaceae > Trillium > subg. Phyllantherum Liliaceae > Trillium > subg. Trillium
Sibling taxa
T. albidum, T. angustipetalum, T. catesbaei, T. cernuum, T. chloropetalum, T. cuneatum, T. decipiens, T. discolor, T. erectum, T. flexipes, T. foetidissimum, T. gracile, T. grandiflorum, T. kurabayashii, T. lancifolium, T. ludovicianum, T. luteum, T. maculatum, T. nivale, T. ovatum, T. parviflorum, T. persistens, T. petiolatum, T. pusillum, T. recurvatum, T. reliquum, T. rivale, T. rugelii, T. sessile, T. simile, T. stamineum, T. sulcatum, T. underwoodii, T. undulatum, T. vaseyi, T. viride, T. viridescens
T. albidum, T. angustipetalum, T. catesbaei, T. cernuum, T. chloropetalum, T. cuneatum, T. decipiens, T. decumbens, T. discolor, T. erectum, T. flexipes, T. foetidissimum, T. gracile, T. grandiflorum, T. kurabayashii, T. lancifolium, T. ludovicianum, T. luteum, T. maculatum, T. nivale, T. ovatum, T. parviflorum, T. persistens, T. petiolatum, T. pusillum, T. recurvatum, T. reliquum, T. rugelii, T. sessile, T. simile, T. stamineum, T. sulcatum, T. underwoodii, T. undulatum, T. vaseyi, T. viride, T. viridescens
Name authority Harbison: Biltmore Bot. Stud. 1: 158. (1902) S. Watson: Proc. Amer. Acad. Arts 20: 378. (1885)
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