Ageratum L. genus is represented in India by two species- A. conyzoides and A.houstonianum.
These closely related pantropica weed species can be differentiated as follows:
Involucral bracts linear, sharply acute-acuminate, sparsely hairy; Corolla of the florets 1.5mm long, shorter than awned pappus scale…. A.conyzoides L.
Involucral bracts linear setaceous, densely hairy; Corolla of the florets 2.5mm long, as long as or longer than awned pappus …. A.haustonianum Mill.
It (Ageratum houstonianum) has larger and robust plants and flowerheads with more florets than A.conyzoides.
In A conyzoides plants and phyllaries are not that densely hairy, and heads are smaller and more spreading
Thicker cordate leaves and longer hairs especially on involucre bracts are clearly seen in Ageratum houstonianum.
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Ageratum page (Asteraceae (Compositae)) with images of species in efloraofindia : 3 posts by 1 author.
Pl. go through Ageratum page (Asteraceae (Compositae)) with images of species in efloraofindia (mainly done by …).
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