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Cuscuta

See list of 11 species in this genus

Herbarium specimens of Cuscuta are much more difficult to interpret than living populations as many structures dry and become less obvious. Careful notes on corolla lobe orientation, numbers of perianth parts, etc., will make specimen review easier. C. epilinum Weihe was reported from MA by Knowlton and Deane (1923b), but specimens are unknown. Reports of C. epilinum from VT were based on a collection of C. epithymum. References: Yuncker (1932), Costea et al. (2006a, 2006b, 2006c).

  • 1a. Stigmas filiform, elongate-tapering, much taller than wide [Fig. 589]; fruit a pyxis, circumscissile near the base
    • 2a. Perianth mostly 4-merous; lobes of the calyx obtuse at the apex; infrastaminal scales bifid and lacking a fringe; seeds ca. 1.5 mm long
    • 2b. Perianth mostly 5-merous [Fig. 589]; lobes of the calyx acute at the apex [Fig. 589]; infrastaminal scales simple and fringed; seeds up to 1.3 mm long
      • 3a. Connate portion of the calyx gold-yellow, lustrous, and with a prominent cellular-reticulate pattern; calyx lobes terminated by a short, fleshy, cylindrical appendage
      • 3b. Connate portion of the calyx not gold-yellow, dull, without a prominent cellular-reticulate pattern; calyx lobes not terminated by a cylindral appendage
  • 1b. Stigmas capitate, dilated near the apex, not or only slightly taller than wide; fruit a utricle or an irregularly rupturing capsule
    • 4a. Sepals distinct; flowers subtended by 3–5 imbricate bracts; seeds (1.9–) 2–2.6 mm long
    • 4b. Sepals connate at the base; flowers not individually provided with bracts; seeds 0.9–2.2 mm long
      • 5a. All or many flowers with a 4-merous corolla [Fig. 591]
        • 6a. Corolla lobes obtuse or rounded at the apex; tips of the calyx lobes not reaching the sinuses between the corolla lobes
        • 6b. Corolla lobes acute to acuminate at the apex; tips of the calyx lobes reaching or surpassing the sinuses between the corolla lobes
          • 7a. Calyx lobes obtuse at the apex; corolla lobes relatively smooth, not granulate-textured, the tip of lobes erect or ascending; pedicels absent or shorter than the flowers; marcescent corolla persistent around the base of the fruit
          • 7b. Calyx lobes acute at the apex; corolla lobes appearing granulate-textured due to thickened outer cells, the tip of lobes inflexed [Fig. 590]; pedicels usually as long or longer than the flowers; marcescent corolla forming a cap over the fruit (though sometimes falling off early)
            • 8a. Flowers 2–5.3 mm long; infrastaminal scales adnate to the connate portion of the corolla for to ½ (rarely ¾) of their length, subspathulate to spathulate in outline, rarely 2- or 3-lobed, rounded to truncate at the apex, with (6–) 20–35 (–50) fimbria; dried capsules brown-yellow to light brown, somewhat translucent, 0.8–1.5 times as long as wide, with scarcely depressed suture lines beteen the 2 carpels (in part)
            • 8b. Flowers 1.7–2.6 (–3) mm long; infrastaminal scales united with the connate portion of the corolla for most of their length, oblong, bifid with 1–3 fimbria 
on each side of the filament attachment (rarely truncate and with 3–6 fimbria); dried capsules brown, opaque, 1.6–2.4 times as long as wide, with depressed suture lines between the carpels that form a groove on each side of the fruit
      • 5b. Flowers with a 5-merous corolla [Fig. 590]
        • 9a. Corolla lobes obtuse at apex, not inflexed at the tip [Fig. 590]; tips of the calyx lobes not reaching the sinuses between the corolla lobes (except in var. latiflora); fruit globose to ovoid to conical; stylopodium present
        • 9b. Corolla lobes acute at apex, usually inflexed at the tip [Fig. 591]; tips of the calyx lobes ± reaching or slightly surpassing the sinuses between the corolla lobes (usually not reaching the sinuses in C. indecora); fruit usually globose to depressed-globose; stylopodium absent
          • 10a. Calyx lobes acute to narrow-obtuse at apex; corolla lobes erect to ascending; flowers with a faint sweet smell in life; marcescent corolla calyptrate (i.e., forming a cap over the fruit, eventually detaching at base and pushed off like a lid) 
 (in part)
          • 10b. Calyx lobes broad-obtuse at apex; corolla lobes spreading to reflexed; flowers inodorous in life; marcescent corolla persistent around the base of the fruit
            • 11a. Calyx lobes ovate-triangular, not or scarcely overlapping at base (except in some newly opened flowers), thus the calyx ± circular when viewed from above; flowers (1.9–) 2.1–3.6 mm long; anthers (0.3–) 0.4–0.5 mm long; seeds 1.1–1.5 mm long
            • 11b. Calyx lobes broad-ovate to rhombic, broadly overlapping at base, protruding to form angles (note: this most visible on mature flowers, it is often obscured in fruit), thus the calyx 5-angled when viewed from above; flowers 1.4–2.1 (–2.5) mm long; anthers 0.25–0.3 (–0.35) mm long; seeds 0.9–1.1 mm long

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