Here are features which will never fail you
1. Calyptocarpus has low growing, procumbent to ascending, mat forming habit often rooting at nodes, rarely rising more than 15 cm, Synedrella tall erect habit up to 80 cm tall.
2. Leaves the most crucial are not longer than 3 cm, pale green, thinner,
faint 3 basal vein and broadly ovate. In contrast leaves of Synedrella are longer than 3 cm, dark green in colour, more prominent basal veins and ovate to elliptic in shape.
3. All heads in Synedrella are in sessile clusters, but in Calytocarpus there are always a few on long peduncles bearing solitary head, in addition to several sessile in cluster.
Apart from trailing habit and smaller leaves I don’t find any consistent character. Both (Calyptocarpus vialis and Synedrella nodiflora) may or may not have three basal veins, heads may be more than one in both.
Synedrella: Plants annual, erect or ascending, not rooting at nodes; heads aggregated; disc florets 4-12; cypsellae of ray florets with lacerate winged margins.
Calyptocarpus: Perennial, prostrate or decumbent, rooting at nodes; heads solitary at each node; disc florets 10-20; cypsellae of ray florets not winged
S. nodiflora: Plants erect, up to 1.5 m tall, dichotomously branches; leaves usually at dichotomies, 3-10 cm long, 1.5 cm broad; heads 1-4 ; invol. bracts 1-2, foliaceous, ray floret achenes with lacerate wings
C. vialis: Plants prostrate, rooting at nodes, irregularly branched; leaves 3-4 cm long, 2-3.5 cm broad; invol. bracts 4, ray floret achene not lacerate
Re: completed insertion of images of Synedrella : 1 post by 1 author.
there is 1 species only
Synedrella page (Asteraceae (Compositae)) with images of species in efloraofindia : 1 post by 1 author.
If you find any mis-identification, pl. let us know.
If anybody can send images of other species of this genera (for incorporation in the website), it will be really nice. Also, if anybody is interested to take up the activity of inserting images on efloraofindia pages from efloraofindia posts, pl. let us know.