Micromorphology of Barleria albostellata (Grey Barleria) Flower and Pollen Grains

Barleria albostellata C.B. Clarke (grey barleria, Acanthaceae) is an indigenous shrub to South Africa and has been relatively understudied. This shrub is a valuable medicinal plant with a wide spectrum of antibacterial and anti-inflammatory activities. Detailed studies on the floral and pollen morphology on B. albostellata are rare. This study was conducted to observe the morphology of the flower and pollen grains using stereomicroscopy and scanning electron microscopy (SEM). Morphological observations showed numerous non-glandular trichomes on the bracteoles and bracts of B. albostellata. Three types of trichomes were identified on these structures: I-unicellular, II-multangulate-dendritic branched non-glandular trichomes, and III-capitate glandular trichomes. A taxonomical description of the floral structures using stereo and SEM micrographs is provided. SEM micrographs revealed the pollen grains as globose tricolporate with a rough honeycomb exine, and small granules inside the lumina. The diameter of the pollen grains was 77.53 & PLUSMN; 5.63 & mu;m, whereas the aperture of these grains was 14.31 & PLUSMN; 0.59 & mu;m. This study provides insight into the floral biology of B. albostellata, and the results presented here will add to the body of knowledge and encourage further research on this species.

Automated summary

Barleria albostellata C.B. Clarke (grey barleria, Acanthaceae) is a medicinal shrub native to South Africa with broad-spectrum antibacterial and anti-inflammatory activities. This study used stereomicroscopy and scanning electron microscopy (SEM) to observe the morphology of its flowers and pollen grains. The observations revealed the presence of three types of trichomes on the bracteoles and bracts, and the pollen grains were tricolporate with a rough honeycomb exine. This study provides valuable insights into the floral biology of B. albostellata, contributing to the existing knowledge and encouraging further research on this species.