The present study was carried out from 346 skulls of Praomys jacksoni (Muridae) captured in some forest areas of the surroundings of Kisangani city (island, right and left banks of Congo River) from 1994 to 1999). The results obtained from twenty-five skulls measurements revealed the diversity existing inside each population studied. The sexual dimorphism is favorable to males for seven measurements (GRLE, HEBA, DIA1, DIA2, INT, LNAS, and LOTE) whereas eighteen remain stable. The skulls of insular populations (Tundulu and Mbiye) are bigger than those of the forest reserves ( Masako and Yoko) for twenty measurements: GRLE, PRCO, HEBA, HEPA, DIA1, DIA2, INT, ZYPL, PAL, UPTE, UPDE, M1, BNAS, LNAS, BUL, DIN, HRZ, ROH, ROB and PCPA The skulls of Mbiye island populations are bigger than those of Tundulu island for eighteen measurements (GRLE, PRCO, HEBA, HEPA, PAF, DIA1, DIA2, ZYG, UPTE, UPDE, M1, ZYPL, BNAS, LNAS, LOTE, CHOA, DIN, PCPA). The skulls of populations from the left bank (Yoko forest reserve) are bigger than those of the right bank for six measures (GRLE, HEBA, DIA1, INT, CHOA and PAF). These results indicate that craniometrical measurements of the adult animals are stable and constitute a complementary means for identifying the species in the Praomys genus. The variations observed with certain examined characters would be the consequence of the biological phenomenon of speciation. It is thus desirable that molecular studies are carried out on these muridae in order to validate this hypothesis.

A floristic inventory of grass and undergrowth was carried out in the southern block of the Yoko Forest Reserve in the Eastern Province. This study aimed to identify grasses and undergrowth, and evaluate the wealth of this areal florula. Transect methods and phytosociological survey was the approach used. A total of 116 plant species have been inventoried and are belonging to 92 genera and 44 families. Note that the dominant families and features are: Commelinaceae (7.76%) and Rubiaceae (6.90%). The relative densities of species and the highest are those of family Marantochloa congensis (174.0 feet/ha) and Marantaceae (360.0 feet/ha). The relative frequencies of the most observed species are those of Palisota barteri (3.21%) and Cola congolana (3.39%), while those of family are Arecaceae, Commelinaceae, Connaraceae, Euphorbiaceae, Lomariopsidaceae, Malvaceae, Marantaceae and Menispermaceae (6.25%). Simpson's diversity index (0.957), Shannon’s diversity index (3.619) and equitability (0.798) revealed that this florula is diversified and its species are well distributed. It is thus desirable that this study is extended to other forest reserves and forest groupings of Kisangani city and its surroundings in order to establish a better database necessary for the sustainable management of the classified forests and other sites of high value for the conservation.