Inventory of Ferns (Class: Filicinae) in West Block, Batang Toru Forest, North Tapanuli North Sumatra

. Batang Toru Forest is one of the conservation areas in North Sumatra which has a diversity of flora and fauna, one of which is ferns. A study on ferns in the Batang Toru Forest area has never been carried out, so the species diversity and distribution are unknown. Ferns are classified into 4 classes, one of which is the Filicinae class. The class Filicinae is a group of ferns that has the highest number of species. This study aims to inventory the class Filicinae ferns in the Batang Toru Forest area by using the exploration method, namely exploring along the track. Found 52 species of ferns belonging to 14 families and 29 genera. Of the 52 species found, 33 species were classified as terrestrial ferns and 19 types of epiphytic ferns.

All types of ferns found were recorded according to their respective locations, by noting their morphological characters (roots, rhizomes, stipe, enthales, sorus, spore color, spore arrangement and spore location). Specimens of all individuals found, collected and labeled hanging. Specimens were arranged and wrapped in newsprint and put in a plastic bag and doused with 70% alcohol.
Exploration results from the field were brought to the laboratory, replaced with newspapers and hanging labels, arranged in such a way and pressed using a sack. Dry in the oven to a constant e. Paku's relatives (Sastrapraja and Afrisiani, 1985).

Data analysis
Data on fern species are presented in the form of morphological descriptions and identification keys. The data is equipped with altitude, location of coordinates, humidity, photos and a general description of the habitat of each fern species found.

Diversity of Ferns
Based on research that has been conducted in the Batang Toru forest area, the results obtained are 52 species of terrestrial ferns and epiphytes, consisting of 14 families and 29 genera, of the 52 species found 33 species belonging to terrestrial ferns and 19 species of epiphytic ferns (Table 1).
). The most common types of ferns found in the study area were from the Polypodiaceae tribe with 10 species, followed by the Lindsaeaceae tribe with 8 species.
The number of ferns in this research location is more than the number of ferns reported by [5] in the Mount Sinabung Forest, which is 44 species and in the research conducted by [1] in the Mount Sinabung Forest, the number of ferns is 44 species. The types of ferns obtained were 32 species.
However, the number obtained in this study is less when compared to the number of fern species obtained in [2] research in the Telagah Forest of Gunung Leuser National Park, which is 56 species and in [3] in the Gunung Sibuatan Forest area, the fern species found in the Gunung Leuser National Park are 56 species. obtained as many as 55 types. In general, in mountainous areas, the number of ferns is more abundant than in the lowlands. [6] , Polypodiaceae is the Pterydophyta family with the highest number of species. The Polypodiaceae family is a fern that has a very high species diversity in the tropics. [7] states that the difference in the number of species and types of ferns in an environment is influenced by several factors such as habitat, adaptability and the environment. [8] stated that in general the more extreme environmental conditions, either due to soil climate or drought, the species diversity decreases and one or two species becomes more dominant.

Habitat
The habitat of ferns is terrestrial and some are epiphytic. In this study, 33 species of terrestrial ferns were found and 19 species of epiphytic ferns were found. Terrestrial ferns include Asplenium tenerum, Dipteris conjugata, Diplazium bantamense, Cyathea moluccana, Gleichenia hirta,

Fern Ecology
The types of ferns at the research site have varied habitats with an altitude of 850 to 1043 m above sea level, humidity of 77 to 98%, soil temperature 19 to 24°C, soil pH 5 to 7°C and light intensity 120 up to 230 Cd. According to [9], a large number of ferns grow terrestrially, with sizes that vary greatly from small to large. Ferns have a fairly high adaptability so that they can adapt to conditions and high humidity and some are tolerant of dry air and soil. Epiphytic ferns are found in large trees, namely on tree branches, on small trees, attached to the ground and also on rocks in slightly open areas, rocks on the edge of rivers or forests. According to [10], that plants found in soils with a pH range between 3 to 9 and extreme acidity is a stress that can be adapted by