<p>The aim of this present study is to summarize the current state of research on the flora of the Côte d’Ivoire from the SIG IVOIRE database to better direct future collection efforts. Herbarium specimen data used for this study covered the period from 1894 to 2000, and were assembled by 226 collectors. This database comprises 15,228 samples, grouped in 3621 species, 1371 genera, and 198 families. A grid system was used to cover the Ivorian territory at spatial resolution of 0.75° x 0.75°. Indices of evenness and completeness were calculated to characterize sampling and identify floristically well-known regions. The exploration of the Ivorian territory is far from uniform, such that some areas were more densely surveyed, but others partially or not at all. The regions of Grands Ponts, Agnéby-Tiassa, Loh-Djiboua, part of Gbèkè, Boukani, San Pedro and Cavally were floristically well known; environmentally, the largest gaps in coverge were in the mountains in western Côte d'Ivoire.<strong></strong></p>

Weeds are the most important biological constraint reducing rice production. This study was conducted to know the physiological characteristics and the germinative behavior of the seeds of Rottboellia cochinchinensis, Euphorbia heterophylla and Porophyllum ruderale, three major weeds of rice field in Côte d'Ivoire. Seed characteristics were determined according to ISTA's standards. These three weeds had orthodox seeds with low moisture content (< 15%). These weeds raise better when they were sown on the surface (0-0.5 cm) or slightly buried in the ground. E. heterophylla and P. ruderale germinated well when their seeding density is high (150 seeds/Petri dish). For R. cochinchinensis, when the seedling density is low (25 seeds/Petri dish). The germination was maximum after five to nine days. RésuméLes mauvaises herbes constituent l'une des contraintes biologiques les plus importantes entrainant une baisse de la production du riz. Cette étude a été menée en vue de connaître les caractéristiques physiologiques et le comportement germinatif des semences de Rottboellia cochinchinensis, de Euphorbia heterophylla et de Porophyllum ruderale, trois adventices majeures des rizières de la Côte d'Ivoire. Les caractéristiques physiologiques ont été déterminés selon les normes de ISTA. Ces trois adventices possèdent des semences orthodoxes qui ont une teneur en eau inférieure à 15 %. Ces graines lèvent mieux lorsqu'elles sont semées en surface (0 cm) ou à une faible profondeur de 0,5 cm. E. heterophylla et P. ruderale germent mieux lorsque leur densité de semis est forte (150 graines/boîte de Pétri). Par contre les semences de R. cochinchinensis germent mieux lorsque la densité de semis est faible (25 graines/boîte de Pétri). Pour ces trois adventices, la germination est maximale au bout de cinq à neuf jours.

Weeds are the most important biological constraint reducing rice production. This study was conducted to know the physiological characteristics and the germinative behavior of the seeds of Rottboellia cochinchinensis, Euphorbia heterophylla and Porophyllum ruderale, three major weeds of rice field in Côte d'Ivoire. Seed characteristics were determined according to ISTA’s standards. These three weeds had orthodox seeds with low moisture content (< 15%). These weeds raise better when they were sown on the surface (0-0.5 cm) or slightly buried in the ground. E. heterophylla and P. ruderale germinated well when their seeding density is high (150 seeds/Petri dish). For R. cochinchinensis, when the seedling density is low (25 seeds/Petri dish). The germination was maximum after five to nine days.

The cocoa tree, the mainexport crop in Côte d'Ivoire is frequently attacked by a disease: brown pod rot, caused by Phytophthora spp. which causes a considerable drop in production. This soil-borne pathogen attacks on so-called weeds when environmental conditions are favourable. The presence of these susceptible weed hosts can amplify this scourge of brown rot by transmitting the pathogen to the crop plant. In order to improve the yield of this crop, a study was conducted in the Nawa region to identify the weed hosts through the characterization of the pathogen. This study consisted first in the inventory of susceptible host weeds of Phytophthora spp. and second in the morphological characterization of the pathogen. Concerning the host weeds inventory we procceeded determining all symptomatic weeds located within 3 m of the cocoa plants affected by brown rot. We identified 48 susceptible host species, divided into 41 genera and 22 families and we observed brown spots on the leaves of Oplismenus burmannii and Laportea aestuans; on the leaves of Clerodendrum splendens and Xanthosoma mafaffa, brown necroses surrounded by a yellow halo were noticed. Oily brown spots were examined on the leaves of Ageratum conyzoides. On the proximal, lateral and distal parts of the pods symptoms of brown spots covered with whitish mycelia were observed. Phytophthora strains obtained from the pods and weeds on PDA culture medium were characterized by matted, white mycelial colonies with a cottony appearance. Microscopic features revealed the presence of sporocysts, oospores and chlamydospores of different shapes.