Silver-Spine Thistle
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Silver-Spine Thistle
P Native Unknown Photo: Thingnam Girija
Common name: Silver-Spine Thistle
Botanical name: Cirsium argyracanthum    Family: Asteraceae (Sunflower family)
Synonyms: Carduus argyracanthus, Cirsium royleanum, Cirsium tibeticum

Silver-Spine Thistle is a perennial herb 30-100 cm tall. Flower-heads are purple, few to many, in erect spike-like cluster, surrounded by pectinately spiny bracts with pungent spines up to 1.5 cm. Florets are bisexual, purple or white, about 1.6 cm, tube about 8 mm. Involucre is ovoid, 1.5-2 cm in diameter, hairless. Phyllaries are overlapping, in about 6 rows; outer phyllaries triangular, 7-8 x 1.5-2 mm, narrowed into a 3-4 mm spine; middle phyllaries lanceshaped to ovate-lanceshaped, about 10 x 2 mm, lacking membranous wings, narrowed into a 2-3 mm apical spinule; inner phyllaries linear-elliptic to broadly linear, about 13 x 2-3 mm, apically expanded into a scarious appendage. Stems are erect, branched above, unwinged, with sparse long multicellular hairs, also cobwebby above. Leaves are concolorous, green, surface smooth, with long multicellular hairs along veins. Middle stem leaves stalkless, elliptic-lanceshaped to elliptic, 8-14 x 2-4 cm, pinnately divided, eared semistem-clasping; segments 4-9 pairs, each with 3-5 unequal teeth with 1-2 mm lateral spinules and a 4-7 mm apical spine. Upper stem leaves with sparse teeth tipped with a 0.7-1.4 cm spine. Achenes are yellowish, about 3 mm. Pappus bristles brownish, about 1.4 cm. Silver-Spine Thistle is found in the Himalayas, at altitudes of 2100-3700 m. Flowering: June-October.

Identification credit: Pravir Deshmukh, Balkar Singh, J.M. Garg Photographed in Tawang, Arunachal Pradesh.

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