Abstract. Sofiyanti N, Sari AK, Iriani D, Mutrofin R, Taufiq I, Juliantari E, Pranata S. 2021. Morphological and anatomical study of four Pyrrosia (Polypodiaeae) species from Rumbai forest, Riau Province, Indonesia. Biodiversitas 22: 4905-4914. Pyrrosia is one of genera in Polypodiaceae that is commonly distributed at Riau Forest, Indonesia. However, the detailed morphological characteristics and anatomical study of Pyrrosia in this region is scanty. This study was aimed to characterize the morphology and anatomy of four Pyrrosia species (P. angustata, P. lanceolata, P. nipoboloides and P. piloselloides) from Rumbai Forest, Riau Province. All of the specimens were collected in the field. Morphological characters were examined in detail. Anatomical preparation was conducted using the paraffin method. The specimens were then observed and photographed using a light microscope. Principal Component Analysis had been carried out using a total of 52 morphological and anatomical characters. The result showed the morphological variation among the species, especially on the shape of sterile lamina and sori characteristics. Anatomically, the examined species showed variations in outline shape in the transverse section of rhizomes and stipes, schelerenchymatous sheath and strand, as well as number of meristele. The PCA results showed that only three characters (shape of sterile laminae, base of sterile laminae, and upper surface color of sterile laminae) have eigenvalue over 1.00 and together these explain 100% of the total variability of the data. The anatomical data in this study is reported for the first time on Pyrrosia from Riau province.

Abstract. Sofiyanti N, Iriani D, Taufik I, Sari M, Irawan A, Syauqi FM. 2021. Diversity, structure and composition of pteridophyte in varying habitats in Karimun Besar Island, Riau Islands Province, Indonesia. Biodiversitas 22: 4847-4856. Biodiversity of small islands, particularly in tropical region, always encourages scientific curiosity. Such curiosity is much greater when the small island of interest has been through various land use changes, such as in Karimun Besar Island. This island is one of thousand islands in Riau Islands Province, Indonesia and poses different land uses. However, studies on the biodiversity of flora in this island have not been recorded, including for pteridophyte or fern members. This study aimed to examine the diversity, floristic structure and composition of pteridophyte at six different study sites in Karimun Besar Island representing varying habitat conditions (i.e., primary forest, secondary forest, rubber plantation, road side, coastal area and mined land. The sampling was collected by using transect method to measure density, dominance and frequency. A total of 32 species of pteridophytes were recorded from the six study sites that belong to two divisions, Polypodiophyta (31 species) and Lycophyta (1 species). The number of species of pteridophyte varied across the six habitats. The highest number of species (21) was found in primary forest, while the lowest (9 species) was found in rubber plantation. The dominant species for each study site were Taenitis blechnoides (Pteridaceae) (rubber plantation), Dicranopteris linearis (Gleicheniaceae) (secondary forest), Sticherus truncates (Gleicheniaceae) (primary forest), Pteridium caudatum (Dennstaedtiaceae) (road side), Achrosticum aureum (Pteridaceae) (coastal area) and Nephrolepis hirsutula (Nephrolepidaceae) (mined land). The result of this study provides the first data of fern in Karimun Besar Island that support pivotal information on the biodiversity of small islands in tropical region.