Pollen and seed morphology of selected species of Andrographis (Acanthaceae) from India

Light and scanning electron microscopic studies of pollen and seeds were carried out for nine species of Andrographis (Acanthaceae) from India. Pollen in all species is isopolar, radially symmetric and tricolporate with elongated apertures, oblate-spheroidal in A. ovata, prolate-spheroidal in A. alata, prolate in A. echioides and A. macrobotrys to sub-prolate in A. lineata var. lawii, A. lineata var. lineata, A. paniculata, A. producta and A. serpyllifolia and lobate-circular to triangular amb. Surface ornamentation is bireticulate except in A. alata, which has microperforate and spinulate tectum. Seeds are obovoid, oblongoid, subquadrate or ellipsoid in shape. The seed coat is covered with hair in A. ovata and with echinate protuberances in A. echioides and A. serpyllifolia. The pollen characteristics of A. echioides including the colporate apertures, prolate shape, bireticulate tectum and verrucate aperture membrane are support an inclusion of this species in Andrographis, rather than considering it as Indoneesiella echioides, which has been the subject of much debate.