Symphyotrichum laeve

Smooth Aster, aster lisse

Symphyotrichum laeve (L.) Á. Löve & D. Löve is widely distributed heterophyllous species across much of Canada and the US (Brouillet et al. 2006; FNA).  The species has been introduced in Mexico in Europe where is occurs in typical form and in forms likely originating from interspecific hybridization in gardens. Leaves are glaucous, thick, firm, ± fleshy, margins crenate-serrate or -serrulate or entire, scabridulous, apices mucronulate; basal leaves usually withering by flowering or sometimes persistent (var. purpuratum), petiolate (petioles ± winged, bases dilated, sheathing), blades spatulate or oblong to ovate or lanceolate-ovate, bases attenuate or cuneate to rounded; mid stem leaves petiolate or subsessile or sessile (petioles narrowly to broadly winged, clasping), blades ovate or oblong-ovate to lanceolate or linear-lanceolate, progressively reduced distally (abruptly so in arrays), bases auriculate and ± clasping to rounded, margins entire; rays usually pale to dark blue or purple, seldom white. The species is hexaploid 2n=48 throughout its range.

Four varieties are recognized here (FNA links include synonyms, e.g. Symphyotrichum attenuatum).

Leaves lanceolate to ovate, conspicuously auric­ulate-clasping, lengths less than 5 times widths  

    Phyllaries strongly unequal, green apical zones diamond-shaped; northeastern onto prairies race  ....  Sy. laeve var. laeve (FNA)
    Phyllaries unequal, green apical zones lanceolate; western prairie and mountain race  ....  Sy. laeve var. geyeri (FNA)

Leaves linear-lanceolate to linear, slightly auriculate-clasping, lengths often 5 times widths        
                  
    Basal leaves withering by flowering, cauline linear-lanceolate eastern race ....  Sy. laeve var. concinnum (FNA)
    Leaves mostly basal and proximal at flowering, mostly linear southeastern race ....  Sy. laeve var. purpuratum (FNA)