Inflorescences monochasial cymes: corymbiform, fasciculate, glomerulate, paniculiform, racemi­form, ropelike, spiciform, or umbelliform. Pedicels 0–10 mm. Flowers sometimes originating endogenously; styles 2, unequal; stigmas globose. Capsules: indehiscent or dehiscence circum­scissile. Seeds angled (2 flat faces and 1 convex), globose, obcompressed, oblong, ellipsoid, obovoid, or ovoid; seed coat epidermis cells honeycombed when dry and papillate when wet.

Distribution

North America, Mexico, West Indies, Central America, South America, Asia, Australia, introduced nearly worldwide.

Discussion

Species 153 (45 in the flora).

Cuscuta australis R. Brown, known from Asia and Australia, was collected in Jefferson County, New York, in 1926 (NY); it is not known to be established or recurrent in the flora area.

Cuscuta veatchii Brandegee is known only from Baja California, Mexico; it does not grow in the flora area.

Evolution of gynoecia with two unequal styles may have been the key evolutionary innovation that spurred the considerable species diversity encountered in subg. Grammica. The two stigmas mature sequentially and are receptive at different times (M. A. R. Wright et al. 2011). Cases of reticulate evolution have been discovered in subg. Grammica (S. Stefanović and M. Costea 2008; Costea and Stefanović 2010; Costea et al. 2015).

Selected References

None.

Lower Taxa

Cuscuta americana, Cuscuta azteca, Cuscuta boldinghii, Cuscuta brachycalyx, Cuscuta californica, Cuscuta campestris, Cuscuta cephalanthi, Cuscuta chinensis, Cuscuta compacta, Cuscuta coryli, Cuscuta cuspidata, Cuscuta dentatasquamata, Cuscuta denticulata, Cuscuta draconella, Cuscuta erosa, Cuscuta glabrior, Cuscuta glomerata, Cuscuta gronovii, Cuscuta harperi, Cuscuta howelliana, Cuscuta indecora, Cuscuta jepsonii, Cuscuta legitima, Cuscuta leptantha, Cuscuta liliputana, Cuscuta mitriformis, Cuscuta nevadensis, Cuscuta obtusiflora, Cuscuta occidentalis, Cuscuta odontolepis, Cuscuta pacifica, Cuscuta pentagona, Cuscuta plattensis, Cuscuta polygonorum, Cuscuta rostrata, Cuscuta runyonii, Cuscuta salina, Cuscuta squamata, Cuscuta suaveolens, Cuscuta subinclusa, Cuscuta suksdorfii, Cuscuta tuberculata, Cuscuta umbellata, Cuscuta umbrosa, Cuscuta warneri

Key

1	Capsules: dehiscence circumscissile.	> 2
2	Styles ± subulate (tapering from base to stigma).	> 3
3	Flowers: calyx and receptacle fleshy, corollas membranous; corolla lobes without hornlike appendages; capsules 4–7 × 4–6 mm.	Cuscuta mitriformis
3	Flowers membranous; corolla lobes each with a hornlike appendage; capsules 1.8–2.5 × 1–2.5 mm.	> 4
4	Pedicels 0.2–0.6 mm; calyx lobes oblong, obovate, ovate, or spatulate, apex acute to obtuse, each exceeded by a hornlike appendage; seeds 0.7–1.1 × 0.7–0.9 mm.	Cuscuta boldinghii
4	Pedicels 1.5–6 mm; calyx lobes oblong-obovate or orbiculate, apex ± truncate, each not exceeded by a hornlike appendage; seeds 0.9–1.4 × 0.8–1.3 mm.	Cuscuta erosa
2	Styles filiform (not tapered; sometimes slightly subulate in C. dentatasquamata).	> 5
5	Calyces divided 1/4 length; seeds 1.	Cuscuta americana
5	Calyces divided 1/3–3/4 length or ± to base; seeds (1 or)2–4.	> 6
6	Infrastaminal scales usually 1/4–1/2 corolla tube length (1/2 to equaling in C. odontolepis).	> 7
7	Inflorescences dense, paniculiform-glomerulate; calyx lobe bases over­lapping; capsules 2.9–4 × 3–3.2 mm; seeds 1–1.2 × 0.6–0.8 mm.	Cuscuta odontolepis
7	Inflorescences loose, racemiform or umbelliform; calyx lobe bases not overlapping; capsules 1.3–2.2 × (0.7–)1.5–2.3 mm; seeds 0.6–0.9(–1.1) × 0.3–0.8 mm.	> 8
8	Flowers 5-merous; calyx lobe midveins carinate; corolla lobes erect.	Cuscuta tuberculata
8	Flowers (3 or)4-merous; calyx lobe midveins not carinate, sometimes with multicellular protuberances; corolla lobes spreading to reflexed.	> 9
9	Calyces 1/3–1/2 corolla tube length; infrastaminal scales 1/2 corolla tube length.	Cuscuta leptantha
9	Calyces equaling corolla tube length; infrastaminal scales 1/4–1/3 corolla tube length.	Cuscuta liliputana
6	Infrastaminal scales equaling or longer than corolla tube.	> 10
10	Pedicels 2–10 mm; calyx lobe midveins not carinate, without multicellular protuberances.	> 11
11	Flowers 4–5.5(–6) mm; calyx lobe apices acuminate.	Cuscuta legitima
11	Flowers 2–3 mm; calyx lobe apices obtuse to acute.	Cuscuta umbellata
10	Pedicels 0.3–2 mm; calyx lobe midveins carinate and/or with multicellular protuberances.	> 12
12	Calyx lobe bases overlapping, apices obtuse or rounded; corolla lobe apices rounded to obtuse.	Cuscuta chinensis
12	Calyx lobe bases not overlapping, apices acute; corolla lobe apices acute.	> 13
13	Flowers 2–2.6 mm, membranous; calyces straw yellow; infra­staminal scales oblong or rounded, distal 1/2 fimbriate; capsules 1.5–2.5 × 1–1.8 mm.	Cuscuta azteca
13	Flowers 2.6–3.8 mm, fleshy; calyces reddish brown; infrastaminal scales truncate or distally irregularly denticulate or 3–7-fimbriate; capsules 3–4 × 1.8–2.9 mm.	Cuscuta dentatasquamata
1	Capsules indehiscent.	> 14
14	Bracts at bases of flower clusters, pedicels, and/or flowers (or on pedicels) 2–11; calyces divided to base or nearly so.	> 15
15	Pedicels 2–5 mm; inflorescences loose, paniculiform.	Cuscuta cuspidata
15	Pedicels 0–1 mm; inflorescences glomerulate, ropelike, or spiciform.	> 16
16	Inflorescences dense, ropelike, spiraling around and closely appressed to host stem, individual flower clusters not discernible; bracts narrowly triangular to lanceolate, apex recurved.	Cuscuta glomerata
16	Inflorescences dense to loose, glomerulate or spiciform, not ropelike, individual flower clusters discernible; bracts ovate-orbiculate to ovate-triangular, apex erect.	> 17
17	Calyx lobes orbiculate, apices rounded; corolla lobe apices obtuse; seeds 1.9–2.5 × 1.7–2.3 mm.	Cuscuta compacta
17	Calyx lobes ovate, apices acute to cuspidate; corolla lobe apices usually acute, sometimes cuspidate; seeds 1.5–1.7 × 1.1–1.3 mm.	Cuscuta squamata
14	Bracts at bases of flower clusters 1(–3), at bases of pedicels and/or flowers (0 or)1(–3); calyces divided 2/5–2/3 length.	> 18
18	Infrastaminal scales absent.	> 19
19	Corolla lobes ovate-triangular, 1/3–1/2 tube length, apices inflexed.	Cuscuta jepsonii
19	Corolla lobes narrowly lanceolate to lanceolate, shorter than, equaling, or longer than tube, apices straight.	> 20
20	Styles 0.5–1(–1.5) mm; anthers 0.2–0.5 mm; capsules surrounded by, not completely enclosed by, withered corolla (capsule top visible).	Cuscuta occidentalis
20	Styles 1.2–3 mm; anthers 0.6–1.1 mm; capsules surrounded by, sometimes also capped by, withered corolla (capsule top not or barely visible).	> 21
21	Calyces 1/4–1/2 corolla tube length; corolla lobes shorter than or equaling tube; stamen filaments 0.3–0.6 mm.	Cuscuta brachycalyx
21	Calyces 3/4 to equaling corolla tube length; corolla lobes equaling or longer than tube; stamen filaments 0.6–1.1 mm.	Cuscuta californica
18	Infrastaminal scales present.	> 22
22	Infrastaminal scales relatively poorly developed, apically irregularly denticulate, or 2-fid with 1–3 fimbriae on each side of filament attachment, or 2-fid with denticulate wings.	> 23
23	Calyx lobes each with a hornlike appendage 0.5–0.7 mm.	Cuscuta warneri
23	Calyx lobes without hornlike appendages.	> 24
24	Calyx lobe apices obtuse to rounded.	Cuscuta polygonorum
24	Calyx lobe apices acute to long-attenuate.	> 25
25	Flowers fleshy; corolla lobe apices acute, inflexed; styles 0.7–1.8 mm, usually equaling, sometimes longer than, ovary; capsules not translucent, interstylar aperture relatively large; 50–1200 m, not California, Oregon, Washington.	Cuscuta coryli
25	Flowers membranous; corolla lobe apices lance-attenuate, straight; styles 0.3–0.7 mm, 1/4 ovary length; capsules translucent, interstylar aperture relatively small; 1500–2600 m, California, Oregon, Washington.	Cuscuta suksdorfii
22	Infrastaminal scales well developed, notably fimbriate.	> 26
26	Calyx and corolla lobe apices dissimilar: calyx lobe apices obtuse, rounded, or subacute; corolla lobe apices usually acuminate, acute, or subacute, sometimes cuspidate, mucronate, or truncate, usually inflexed (± cucullate in C. draconella).	> 27
27	Calyces 1/2–3/4 corolla tube length; corolla lobes 1/2 tube length.	Cuscuta suaveolens
27	Calyces usually equaling corolla tube length, sometimes shorter (C. runyonii); corolla lobes equaling or longer than tube.	> 28
28	Flowers (3 or)4(or 5)-merous.	> 29
29	Calyces angled, lobe bases overlapping, midvein ± carinate; capsules globose to ovoid; seeds 1 or 2.	Cuscuta harperi
29	Calyces not angled, lobe bases not overlapping, midvein not carinate; capsules depressed-globose; seeds 3 or 4.	Cuscuta polygonorum
28	Flowers (4 or)5-merous.	> 30
30	Calyx lobe midveins with multicellular protuberances.	> 31
31	Calyces ± angled, lobe bases overlapping.	Cuscuta draconella
31	Calyces not angled, lobe bases not overlapping.	Cuscuta runyonii
30	Calyx lobe midveins without multicellular protuberances.	> 32
32	Calyces angled, lobes broadly ovate to rhombic, bases auriculate, overlapping; flowers 1.4–2.5 mm; corolla tubes 0.7–1.2 mm; anthers 0.2–0.3 mm.	Cuscuta pentagona
32	Calyces not angled, lobes ovate-triangular to triangular, not auricu­late, bases overlapping or not; flowers 1.9–4.6(–5) mm; corolla tubes 1.1–2.5 mm; anthers (0.3–)0.4–0.7 mm.	> 33
33	Calyx lobe bases overlapping; capsules to 1/3 enveloped by withered corolla.	Cuscuta campestris
33	Calyx lobe bases not or slightly overlapping; capsules 1/2+ enveloped by withered corolla.	> 34
34	Perianths papillate (sometimes not obvious in calyx); corollas drying reddish brown to yellow, tube cam­panulate, later globose, saccate between lines of stamen attachments; infrastaminal scales equaling or longer than corolla tube.	Cuscuta glabrior
34	Perianths not papillate; corollas drying creamy white, tube narrowly campanulate to cylindro-campanulate, not saccate between lines of stamen attachments; infra­staminal scales 3/4–4/5 corolla tube length.	Cuscuta plattensis
26	Calyx and corolla lobe apices similar: calyx lobe apices either: 1) usually acuminate, acute, long-attenuate, and rarely cuspidate (C. subinclusa) or subacute, or 2) usually obtuse to rounded; corolla lobe apices acuminate, acute, long-attenuate, cuspidate (C. pacifica and C. salina), obtuse, or rounded, usually straight, rarely inflexed (C. indecora) or recurved (C. howelliana).	> 35
35	Calyx lobe apices obtuse to rounded; corolla lobe apices obtuse to rounded.	> 36
36	Calyces straw yellow, reticulate, shiny, lobe margins denticulate; seeds 1, globose to globose-ovoid.	Cuscuta denticulata
36	Calyces yellow-brown or brownish, not or finely reticulate, or not or slightly shiny, lobe margins usually entire, sometimes serrulate; seeds (1 or)2–4, ± angled, ellipsoid, obcompressed, oblong, obovoid, ovoid, or subglobose.	> 37
37	Flowers (3 or)4(or 5)-merous.	Cuscuta cephalanthi
37	Flowers (4 or)5-merous.	> 38
38	Calyces equaling corolla tube length; capsules depressed-globose, not raised or thickened around interstylar aperture.	Cuscuta obtusiflora
38	Calyces usually 1/3–1/2 corolla tube length, sometimes equaling corolla tube (C. gronovii var. latiflora); capsules conic-globose, ovoid, or subobpyri­form, raised and thickened around interstylar aperture.	> 39
39	Flowers 4–6(–7) mm; capsules broadly ovoid (with stout beak 1–1.5 mm).	Cuscuta rostrata
39	Flowers 2–4(–4.4) mm; capsules conic-globose, ovoid, or subob­pyriform (rarely apically narrowed into a neck to 1 mm).	> 40
40	Infrastaminal scales equaling corolla tube; styles (0.6–)1.2–2.2 mm; capsules 2.5–4.5(–5.2) mm.	Cuscuta gronovii
40	Infrastaminal scales (1/3)–1/2 corolla tube length; styles 0.3–0.9 mm; capsules 3.5–6.5(–7) mm.	Cuscuta umbrosa
35	Calyx lobe apices usually acuminate, acute, or long-attenuate, rarely cuspidate (C. subinclusa); corolla lobe apices usually acuminate, acute, or long-attenuate, sometimes cuspidate (C. pacifica and C. salina).	> 41
41	Flowers fleshy; corolla lobe apices inflexed.	Cuscuta indecora
41	Flowers membranous or base of perianth and receptacle fleshy (C. nevadensis); corolla lobe apices usually straight, rarely recurved (C. howelliana).	> 42
42	Flowers 5–7(–9) mm; calyces 1/2 corolla tube length; corolla lobes 1/4–1/3 tube length; anthers 0.8–2 mm.	Cuscuta subinclusa
42	Flowers (2.5–)2.8–5(–6) mm; calyces equaling or longer than corolla tube; corolla lobes equaling or longer than tube; anthers 0.3–0.8 mm.	> 43
43	Infrastaminal scales equaling corolla tube; embryo bases globose-enlarged.	Cuscuta nevadensis
43	Infrastaminal scales 1/2–2/3(–4/5) corolla tube length; embryo bases not globose-enlarged.	> 44
44	Flowers embedded in inflorescence of host, 4(or 5)-merous; calyx lobe apices acuminate to long-attenuate; capsules depressed-globose to globose.	Cuscuta howelliana
44	Flowers not embedded in inflorescence of host, 5-merous; calyx lobe apices acuminate to acute; capsules ellipsoid-ovoid or ovoid.	> 45
45	Inflorescences subglomerulate to umbelliform; pedicels 0.5–2 mm; flowers 3.5–6 mm; corolla tubes campanulate, lobes broadly ovate to rhombic-ovate; infrastaminal scales 1/2–3/4 corolla tube length; coastal salt marshes and tidal flats, coastal interdune depressions and grasslands.	Cuscuta pacifica
45	Inflorescences corymbiform; pedicels (0.5–)1–5 mm; flowers 2.5–4.5 mm; corolla tubes ± cylindric-campanulate to obconic, lobes lance-oblong to lance-ovate; infrastaminal scales 4/5 corolla tube length; inland salt flats.	Cuscuta salina