Diversity of types pterodhopita in the campus Universitas Sumatera Utara

Forests in Indonesia that have high biodiversity, including one of them is the type of fern. The characteristic of Indonesian tropical rainforests is that they have high rainfall so that they strongly support the existence of this type of fern. In general, ferns like humid habitat conditions. The purpose of this study was to determine the types of ferns around the campus Sumatera Utara. The method of this research is by roaming, namely exploring each location that can represent the location where there is the most vegetation. The number of types of ferns found on the campus of the Universitas Sumatera Utara is 20 types. There are 9 families in the research location, including the polypodiaceae family as much as 35%, Pteridaceae (20%), Thelypteridaceae (15%), Nephrolepidaceae (10%), Aspleniaceae (10%), Athyriaceae (5%), Dryopteridaceae (5 %) and Blechnaceae (5%). There are 13 types that grow epiphytic and 7 that live terrestrially. The host trees for epiphytic ferns include Swietenia mahagoni, Elaeis guineensis, Gmelina arborea, Samanea saman and Paraserianthes falcataria.


Introduction
The diversity of types of epiphytic ferns in various types of host trees due to their dependence on the micro-climatic conditions of the forest stands, causing the existence of a number of epiphytic fern colonies to be found only in certain tree species or in certain tree parts [1]. Ferns are one of the undergrowth vegetation that are often found in forest ecosystems. Ferns can be used as food and ornamental plants [2]. Ferns and lycophytes are spread globally with a total of 11,000 species [3]. The fern (Pteridophyta) is a division whose citizens clearly have corms, which means that their bodies can be distinguished into three main parts, namely roots, stems and leaves [4].
The Universitas Sumatera Utara campus is included in the green campus with an area of 120 hectares which has green open space with various types of trees that are maintained. Old trees such as Swietenia mahagoni and Tamarindus indica have a diameter of up to 1 meter. Humid shade conditions in several forest locations on the Campus Universitas Sumatera Utara grow ferns, both that grow efficiently on old tree trees and grow terrestrial under stands. Some locations that are overgrown with ferns include Tri Dharma forest, Friendship forest, and Library Park. This study aims to (1) make an inventory of the diversity of ferns in the campus of the Universitas Sumatera Utara (2) to identify the types of host plants that are overgrown by ferns.

Materials and methods
The method of collecting ferns is done by roaming, namely exploring each location that can represent the location with the most vegetation. Several locations were chosen deliberately, namely Tri Dharma Forest, Friendship Park, Library Park. These locations are areas with a lot of vegetation and overgrown with many types of ferns.

Results and discussion
The results showed that there were 20 types of ferns from 9 families in the Campus of the University of North Sumatra. The number of epiphytic ferns was 13 species that grew on various types of trees and 7 species grew terrestrial under stands. Compared to research by [5] in the forest area of Beginjan Village, Tayan Hilir District, Sanggau Regency, there are 14 types of ferns. The ferns in University of North Sumatra environment were terrestrial and epiphytic.
Adiantum latifolium. Long rhizome creeping; dark brown scales [6]. These spikes grow terrestrial under stands which have dense and moist litter. Has a brown stem, green leaf color and elliptical leaf shape. Grow in clumps so that they look beautiful. This fern is an ornamental plant that can be planted in pots both indoors and outdoors. Asplenium nidus. This fern has the local name of bird's nest fern. Has the characteristics of an upright rhizome and is usually large. It is said to be a nest of berung because the leaf arrangement is neatly rounded. Usually this plant is Efipit and is widely cultivated as an ornamental plant. This bird's nest fern is effective in various types of trees such as Swietenia mahagoni trees, cape trees and oil palm plants.
Christella subpubescens. This fern is a terrestrial species that grows in moist, shaded soil. Grows between the litter on the soil surface. The color of the leaves is green and the position of the leaves is alternating on the petiole.
Christella dentata. Christella dentate has dark fibrous roots. This fern has a true stem and lives terrestrial above the soil surface.
Cyclorosus heterecarpus. This fern is a terrestrial type. Has an upright rhizome brown. The leaf stalks are green to brownish color Davallia denticulate. belongs to the Davalliaceae family. The characteristics of these ferns are that they have a round, slender, creeping rhizome. The rhizome has dark brown scales. The green type is round and the surface is smooth. The leaves are dark green on the upper surface (adaxial) and light green on the lower surface (abaxial). The leaf surface is smooth, the texture of the leaves is like paper. Pina is arranged alternately on the rachis. The pinula is ovoid with a tapered tip and a pointed leaf base, and edges with a jig. There are branch bones which are also shaped like black lines under the leaves. The arrangement of these leaf bones is pinnate [5]. Effective in various types of plants such as oil palm. This fern is used as an ornamental plant as well as a bouquet.
Diplazium esculentum. has fibrous roots, stems grow upright green, have a smooth surface with scales. Leaflets are round blunt with leaf bones that form an indentation. The tip of the leaflets has a sharp tip, the leaves are green. sorus is found at the bottom of the leaves, used as a vegetable, can be used as a drug to reduce body heat, can also be used as a drug after childbirth [7].
Dynarian sparsisora. The rhizome is creeping, at the base of the rhizome there is a rhizome with a brown leaf shape. The petiole is clear and has alternate leaves. The shape of the alternating leaf arrangement makes this fern look beautiful. This fern is included in ornamental plants. This fern can be cultivated in pots.