Table 1. Morphological and micro-morphological characters of four Aster species.

Characters	Aster tonglingensis	Aster dolichophyllus	Aster verticillatus	Aster tianmenshanensis
Height	70–100 cm	40–50 cm	25–100 cm	Up to 10 cm
Basal leaves	Long petiolate, lanceolate	Sessile, spatulate	Petiolate, lanceolate	Sessile, spatulate
Adaxial surface of leaves	Puberulent	Glabrous	Scabridulous	Glabrous
Capitula	More than 30, terminal and axillary, 20–25 mm in diameter	Less than 10, terminal, 25–30 mm in diameter	More than 20, terminal and axillary, 10 mm in diameter	Single, terminal, 15–20 mm in diameter
Phyllaries	5–7 series	2–3 series	3 series	2–3 series
Achenes	Beakless	Beakless	Beaked	Beakless
Pappus	Robust	Robust	Readily caducous	Robust
Stigamatic lines	Equal to the sterile style tip appendages	Shorter than the sterile style tip appendages	Shorter than the sterile style tip appendages	Longer than the sterile style tip appendages
Disc corolla lobes	Unequal, split to two thirds or three fourths of limb	Equal, split to one third of limb	Equal, split to one half of limb	Unequal, split to one third of limb
Anther endothecial cells	Polarized thickened	Radially thickened	Radially thickened	Radially thickened
Anther tip appendages	Narrowly triangular, length-width ratio ca. 2	Triangular, length-width ratio ca. 1.5	Triangular, length-width ratio ca. 1.5	Narrowly triangular, length-width ratio ca. 2