Heteroderis

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Heteroderis

Description

Annual herbs with simple or branched, weakly leafy, erect or ascending stems covered with more or less profuse, arachnoid-hairy or tomentose pubescence and setaceous hairs. Cauline leaves alternate, sessile, amplexicaul, uppermost undivided and entire, middle and lower cauline leaves and leaves of basal rosette usually entire und with sinuate-dentate margin, less often runcinately pinnatipartite or pinnatilobate. Capitula in clusters of 3-5 terminal on stem and its lateral branches, with rather numerous florets. Involucre cylindrical, 8-13 mm long, 3-5 mm wide; phyllaries coriaceous-herbaceous, arachnoid-hairy pubescent on the outer side or glabrous, with setaceous hairs often on midrib, scarious along margin; outer phyllaries five, ovate or lanceolate, 1.5-4 mm long; inner phyllaries 8, linear-lanceolate. Receptacle flat, glabrous. Corolla yellow, tube covered with very short erect hairs. Achenes dimorphic; peripheral achenes 8, appressed to inner phyllaries, without beak (less often single achenes with 1-2 mm long beak), curved, narrowed above, with 5 longitudinal ribs, surface without scales and tubercles; pappus of few bristles equally in length; central achenes numerous, achene body 2.5-3 mm long and c. 0.5 mm wide, narrowly cylindrical, narrowed toward the base, with 5 longitudinal ribs and covered with small acute tubercles in the upper part or over the entire length (often only on one to three ribs), gradually modified in the upper part to deflected acute scales; beak slender, 2-7 mm long, smooth, without articulation at the base, pappus of numerous very shortly fimbriate bristles equally in length.

adapted from Leonova in Bobov & Tzvelev (1964: 587-588 [Engl. transl.]). A

Chromosome numbers

Diploid, x = 3.B

Distribution

Africa: Egypt (Egyptnative) Asia-Temperate: Afghanistan (Afghanistannative); Iran (Irannative); Iraq (Iraqnative); Kazakhstan (Kazakhstannative); Kirgizistan (Kirgizistannative); Saudi Arabia (Saudi Arabianative); Tadzhikistan (Tadzhikistannative); Turkmenistan (Turkmenistannative); Uzbekistannative Asia-Tropical: Pakistan (Pakistannative)

Bibliography

A. Bobrov E. G. & Tzvelev N. N., Flora USSR 29. 1964
B. Watanabe K., Index to chromosome numbers in Asteraceae.