Vegetative Characters, Growth Habit and Microsporangiate Strobilus of Lycopsid Minostrobus chaohuensis
Late Devonian Minostrobus chaohuensis is one of the earliest monosporangiate-strobilate isoetaleans. Based on new material of this plant, the vegetative axis and microsporangiate strobilus are studied in detail, and the whole plant knowledge is summarized. The vegetative axis is isotomously branched. The stem is up to 55 mm in diameter with helically arranged leaf cushions. Stems and thick branches bear long fusiform leaf cushions and interareas with vertical linear ornamentations. A ligule pit, oblanceolate leaf scar, and vascular bundle scar appear on the leaf cushion. Distal axes have persistent lanceolate leaves and rhombic leaf bases. The microsporangiate strobilus is cylindrical in shape, possesses sporophyll with alate pedicel and long triangular lamina, uniseriate sporangial wall, subarchesporial pad inside the sporangium, and microspore with cingulum. Based on comparisons with other isoetaleans, the usage of the terms “leaf cushion” and “leaf base” is discussed, and Minostrobus chaohuensis is considered as a tree-like lycopsid. It suggests that arborescent isoetaleans with monosporangiate strobili had appeared and diversified in the Late Devonian. The multi-dichotomous branching system of Minostrobus provides new data on the evolution of growth architecture in rhizomorphic lycopsids.
New insights into the heterosporous lycopsid Changxingia from the Upper Devonian Wutong Formation of Zhejiang Province, China
A heterosporous lycopsid plant is described from the Upper Devonian (Famennian) Wutong Formation, Changxing County, northern Zhejiang Province, China. The plant is known for its terminal and many detached megasporangiate strobili, most of which do not have sporophylls preserved. Some megasporangiate strobili are closely associated with a vegetative axis bearing leaf cushions and with a mass of microspores. Because of the monosporangiate strobili, the present lycopsid belongs to the Dichostrobiles of the Isoёtales sensu lato. This lycopsid conforms to Changxingia in the vegetative leaves, leaf cushions (including leaf scar and ligule pit), some parts of the megasporophyll (pedicel, heel and lamina), the megasporangium and the megaspores, although the branching pattern of axes, the arrangement and other parts of megasporophyll are still unknown. The fossils are described as Changxingia sp., and this genus is expanded with character of microspore. Hence, the previous and present data indicate that the earliest lycopsids with monosporangiate strobili from the Upper Devonian of China are consistent in Lagenicula megaspores with gula and Lycospora microspores with equatorial cingulum. In contrast, the Carboniferous lycopsids with monosporangiate strobili in Euramerica and Cathaysia show great diversification of both megaspores and microspores.
An Internet-based Real-time Heavy Rainfall Display System
A new storm warning system, which can be accessed through the Internet and by cellular phones is described. At the time of a heavy rainfall for disaster prevention, it is important that every resident understand how heavy is that rainfall. A real-time heavy rainfall display system designed for all of Japan provides such information (http://www.disaster-i.net/rain/). In that system values for 1-hour precipitation, 24-hour accumulated precipitation, etc. are displayed at every observatory. Advantages are that not only the latest observations but differences from the historical highest records can be seen. Almost all information is displayed by characters so that users have easy access to the system even when the communication network is crowded. Access date for the six months after the system opened shows that the average daily number of accesses of the top page was 306, and the largest number 3078. The maximum number for daily access to all the pages was about 21,500. This is about 2% of the number obtained on the same day for a similar system operated by the Ministry of Land, Infrastructure and Transport (http://www.river.go.jp/).