Judul: Artabotrys (Annonacea) in East Malesia
Abstrak: Studies on the taxonomy of the genus Artabotrys R. Br. ( Annonaeceae ) in East Malesia were based on morphological characters by examining a large number of Herbarium Bogoriense (BO), Celebense (CEB), Manokwari (MAN), Departemen of Forest Lae (LAE) and living plants of Bogor Botanical Garden. There are eight species which have been known previously: A. camptopetala Diels, A. gracilis King., A. hexapetalus (L.f.) Bhandari, A. inodorus Zipp., A. macranthus Holthuis, A. speciosus Kurz., A. suaveolens Blume, A. sumatranus Miq. and A. venustus King. Four new species are proposed in this treatment : A. desmidantha Diels ex Triasti., A. longipetalus Triasti., A. palmatiflorus Triasti., and A. trichofolius Triasti.. An identification key and detailed discription are provided for taxa. Artabotrys suaveolens Blume is widely distributed. While A. camptopetala, A. desmidantha, A. longipetalus, A. inodorus, A. palmatiflorus and A. trichofolius have a limited distribution. New Guinea is the area with the highest diversity of Artabotrys species in East Malesia. A phylogenetic analysis with Cyathocalyx sumatranus as outgroup, shows three major groups. The first group is Cyatocalyx sumatranus. The second group is A. macranthus which has the closest relationship with the outgroup. The third group separated from the other group by the synapomorph characters 2 (leaf length), 3 (hook), 11 (carpel shape), 14 (number of ovule) and 15 (position of seed).
Keyword: 

Judul: A Taxonomic Reinvestigation of some Biophytum Species (Oxalidaceae)
Abstrak: Biophytum merupakan salah satu tumbuhan yang dimanfaatkan sebagai obat tradisional di beberapa wilayah di Indonesia. Kesulitan mengidentifikasi sekumpulan koleksi Biophytum dari Jawa Barat dan Sulawesi Tengah, menunjukkan perlunya dilakukan penelitian untuk menemukan bukti taksonomi baru dalam merevisi marga Biophytum. Ciri dan sifat ciri morfologi dan anatomi Biophytum yang diamati terutama difokuskan pada ciri yang belum pernah dipergunakan sebelumnya untuk membatasi jenis-jenis Biophytum. Variasi ciri dan sifat ciri morfologi serta anatomi daun yang diamati dianalisis kemiripan dan perbedaannya. Data yang diperoleh kemudian ditabulasi untuk digunakan dalam membuat kunci identifikasi jenis Biophytum. Hasil penelitian menunjukkan bahwa terdapat variasi ciri morfologi pada bentuk permukaan dan warna batang, pelipatan daun muda, ada tidaknya lapisan lilin pada permukaan daun, pola perlekatan tangkai daun tua, keberadan adanya alat perkembangbiakan vegetatif berupa geragih dan tunas adventif, warna gagang perbungaan, warna calon perbungaan pada fase inisiasi, warna dan bentuk kuncup kecil dan kuncup besar, warna mahkota, diameter bunga saat mekar, bentuk dan ukuran buah merekah, serta bentuk biji. Pada ciri anatomi ditemukan variasi keberadaan macam dan letak trikoma, letak dan ukuran stomata, serta bentuk dinding sel epidermis. Semua variasi ciri dan sifat ciri morfologi batang, daun, bunga, buah dan biji, serta juga ciri anatomi daun ternyata dapat digunakan sebagai bukti taksonomi baru untuk membedakan jenis-jenis pada marga Biophytum melalui kunci identifikasi. Berdasarkan variasi ciri dan sifat ciri yang berhasil diungkapkan tersebut, ternyata bahwa kumpulan jenis yang diteliti ternyata terdiri atas lima jenis Biophytum yaitu, B. sensitivum, Biophytum sp. 1 dan Biophytum sp. 2 yang dikoleksi dari Sulawesi Tengah, serta B. dendroides dan B. reinwardtii yang berasal dari Jawa Barat., Biophytum is one of the sources of traditional medicinal herbs in several regions of indonesia. The difficulty in identifying collections of Biophytum from West Java and Central Celebes Province indicates that there is a need to find further taxonomic evidence for classifying species of this genus. Morphological and anatomical characters and character states hardly used in previous studies were analyzed and evaluated to find out their suitability to be used as diagnostic characters in defining each species. Information and data accumulated on the similarity and differences of morphological and leaf anatomical characters are tabulated and used to prepare an identification key. The results showed that there are variations in morphological characters of stem color and surface texture, the folding of young leaves, the presence of wax coating on leaf surface, attachment characteristics of old petioles, the presence of vegetative propagations in the form of stolon and adventive suckers, color and shapes of various generative parts including the peduncle, initial inflorescence and flower buds, size and shape of flowers, the dehiscing fruits, and the seed shapes. Similarly, there are variations in leaf anatomical characters such as the presence, shape, and distributions of trichomes and stomata, as well as the in the shape of epidermal cell walls. In conclusion, those variations in morphology of stem, leaves, flowers, fruits, and seeds, as well as leaf anatomical characters can be used as new taxonomic evidence to distinguish species of Biophytum. Based on the results obtained, it can be concluded that the collections studied represent five
Keyword: Biophytum, taxonomic evidence, morphological and anatomical characters

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
Keyword: