A benthic marine brown alga, Stypopodium cf. flabelliforme Weber Bosse (Dictyotales, Phaeophyceae, Ochrophyta) was collected from the coasts of Chichi-jima Island, Ogasawara Islands, Japan. This alga is different from other species of the genus Stypopodium in having an iridescent, semiprostrate, flabellate blade with broad marginal rhizoidal holdfasts. Anatomical observation on the materials from Chichi-jima Island proved that this species possesses dorsiventrality in the thalli and ability to form polystichous stolons, that have not been reported in this genus. In Japan, it is suggested that has been confused with young stage of Stypopodium zonale (J.V.Lamour.) Papenf. so far.

Algal balls belonging to the genus Cladophora sensu lato, also known as ‘Marimo’ in Japanese, were found in a home aquarium containing rosy bitterling (Rhodeus ocellatus ocellatus). The algal balls were presumed to have originated from bivalves collected from Lake Motosu, which the bitterling use for spawning. Genetic analyses showed agreement with the 18S rRNA gene of Aegagropilopsis clavuligera, registered in GenBank from tropical aquarium in the Netherlands and China. Zoospore formation noted during microscopic observations was consistent with the description of Aegagropilopsis clavuligera and their morphological differences were vague. This is the third species in the ball-forming Aegagropila–Aegagropilopsis group identified in Japan, and has been given the Japanese name ‘Motosu Marimo’.

Three kinds of shoots are recognized in Ginkgo biloba: coppice shoots, long shoots, and short shoots. The most distinctive morphological function of G. biloba coppice shoots is to maintain a live tree crown. Tree trunks of G. biloba have soft weak wood and are easily broken by strong winds such as typhoons. Coppice shoots of G. biloba develop where the tree trunk is cut or broken, or at the trunk base, and grow rapidly, resulting in recovery of trees from disturbance. Both long shoots and short shoots of G. biloba are similar to those of other tree species. Long shoots produce canopy volume while short shoots develop leaves and flowers.

To obtain a better understanding of the floral traits of sect. Heterotropa (genus Asarum, Aristolochiaceae), we conducted a detailed microscopic examination of the surface of the calyx, the floral part best representing the diversity of the lineage. The surface structures were highly variable among Heterotropa species, with remarkable variations in trichome morphology on the adaxial surface of the calyx lobes. Four types of trichome were identified on the calyx lobes, each of which was the sole type in most samples, although combinations of multiple types were occasionally seen. Variations were also found in the distribution of stomata on the surface of the calyx. Although the biological functions of the trichomes and stomata on the calyx are unclear, they may be related to pollination systems, e.g., through emission of the floral scents that are highly variable among Heterotropa species.

The established populations of two ornamental aquatic plant species were discovered in the Kanto region, Eastern Japan, for the first time. Glossostigma elatinoides (Phrymaceae) was found in Tokyo and Ibaraki Prefectures. It expands extensively in the river and possibly propagates by vegetative organs and seeds at the former site. Hygrophila polysperma (Acanthaceae) was also confirmed all-year-round growth in Tochigi Prefecture with sub-zero temperatures during the winter. Therefore, the two alien species poses a concern to further expand the distribution and establishment of both the species.