Nodding Thistle #2 is a photograph by J McCombie which was uploaded on September 18th, 2019.
Nodding Thistle #2
This piece has been featured in the FAA Groups: Macro Photography Only, and Macro Marvels.... more
by J McCombie
Title
Nodding Thistle #2
Artist
J McCombie
Medium
Photograph - Untouched
Description
This piece has been featured in the FAA Groups: "Macro Photography Only", and "Macro Marvels".
The plant bears showy red-purple flowers. The large globose flower heads, containing hundreds of tiny individual flowers, are 3–5 cm (rarely to 7 cm) diameter and occur at the tips of stems. The flower heads commonly droop to a 90° to 120° angle from the stem when mature, hence its alternate name of "Nodding thistle". Each plant may produce thousands of straw-colored seeds adorned with plume-like bristles. They are 4 to 6 cm across, with purple-red bracts. The number of flowerheads per plant is site-dependent and ranges from about 20-50 on good sites and 1-20 on poor sites. Flowering occurs from late spring to late summer, and seed dissemination occurs approximately one month after the flowers form. A single flower head may produce 1,200 seeds and a single plant up to 120,000 seeds, which are wind dispersed. The seeds may remain viable in the soil for over ten years, making it a difficult plant to control.
Flower heads single on slender, smooth, long, bare (not spiny-winged) stalks at ends of branches and from axils of upper leaves, each head large, 4-7.5cm (1½-3in.) across but occasionally smaller, with no ray florets but with many, large, bright purple disk florets, these surrounded by an involucre of many, overlapping, broad-based, greenishbracts with outward- or backward-pointing, long, sharp spiny tips; heads at ends of stems and branches usually bent to one side ("nodding"), those from leaf axils often nearly erect; seeds light brown, shiny,4mm 1/6in. long, egg-shaped with a small knob at the tip and a pappus (parachute) of short, unbranched (non-plumose), light beige hairs.Flowers from June to October.
Stems of second-year plants erect, 30-180cm (1-6ft) high, with harshly spiny, irregularly lobed, leaf-like wings running lengthwise on all stems and branches except just below each flower head; first-year plants forming a large, circular, nearly flat rosette, each leaf often 30cm (12in.) long by 10cm (4in.) wide, bright green to gray-green, margins deeply lobed, the lobes close together, twisted and wavy, with long, sharp spines pointing in all directions; the actual upper and lower surfaces of the leaf blade and its lobes (apart from the harshly spiny margins) finely woolly-hairy and soft to the touch; stem leaves of second-year plants similar to rosette leaves but gradually smaller and less lobed upwards, alternate (1 per node).
Nodding thistle is common throughout southern Ontario in pastures, waste places, roadsides and around buildings, especially on coarse-textured soils.
Carduus nutans is usually a biennial, requiring 2 years to complete a reproductive cycle. However, it may germinate and flower in a single year in warmer climates. Seedlings may emerge at any time from spring to late summer and develop a rosette. Plants overwinter in the rosette stage, sending up a multi-branched flowering stem in mid spring of their second year.
Uploaded
September 18th, 2019
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