First occurrence of Cedrelospermum (Ulmaceae) in Asia and its biogeographic implications.

Cedrelospermum (Ulmaceae) is an extinct genus with extensive fossil records in Europe and North America. However, no fossil of the genus has been reported from Asia. Here we describe Cedrelospermum asiaticum L.B. Jia, Y.J. Huang et Z.K. Zhou sp. nov. based on compressed fruits from the late Miocene of Yunnan, southwestern China. The fossil fruits are characterized by an ovate fruit body adjoined by double wings, with the veins on the primary wing converging toward a stigmatic area. According to the historical geographic distribution of the genus, we hypothesize that Cedrelospermum originated in North America where both single-winged and double-winged fruits were reported. The single-winged form subsequently spread into Europe via the North Atlantic land bridge and the double-winged form dispersed into Asia via the Bering land bridge. From the Eocene to Oligocene, a southward retreat of the genus distribution probably took place, which coincided with the global surface cooling initiated during the Eocene-Oligocene transition. The extinction of Cedrelospermum from Asia may be related to the intensification of the East Asian monsoon.

Pharmacognostic evaluation of leaf and root bark of Holoptelea integrifolia Roxb.

OBJECTIVE: To evaluate the pharmacognostic characters of an important medicinal plant, Holoptelea integrifolia (H. integrifolia) Roxb. METHODS: The pharmacognostic studies were carried out in terms of organoleptic, microscopic, macroscopic and fluorescence analysis. RESULTS: The characteristic microscopic features of leaves were observed as trichomes, multicellular trichomes, xylem cells, phloem cells, collenchyma, vascular bundles, spongy parenchyma and palisade cells. The characteristic microscopic features of root bark included cork cambium, primary cortex, phloem fibers, medullary rays, endodermis, pericycle and lignified fibers in the transverse section and longitudinal section. The characteristic microscopy of root bark powder showed the presence of cortex cells, sieve tubes, calcium oxalate crystals and lignified fibers. Macroscopic study showed that leaf shape-oval, apex-acute, base-cordate and leaf margin was entire with glabrous surface, bitter taste and characteristic odour. The morphological features of root bark showed deep fissured, rough and firm surface with rhitydome and the periderm parallel to cambium. CONCLUSIONS: Various pharmacognostic characters observed in this study help in the identification and standardization of H. integrifolia.

[Structural characteristics of Hemiptelea davidii community on Kerqin sandy land].

An investigation was made on the species composition and eco-type of Hemiptelea davidii community on Kerqin sandy land. The results showed that in study area, no shrub layer existed in H. davidii forest, while arbor layer could be divided into two sub-layers, with a height of 4.05-7.86 m for the upper layer, and of 2.05-3.20 m for the lower layer. In the community, there were 32 herbal species belonging to 27 genera of 13 families and dominant by Poaceae, Fabaceae and Compositae, and 11 areal types, among which, the species number in Mongolian-Northeastern China-Dahuricia-North China areal type was the highest (34.38%), followed by that in Northeastern China-North China areal type (12.5%). Among three water ecological types, mesophytes occupied 59.37% of the total, and mesoxerophytes and xerophytes occupied 25% and 15.63%, respectively. Hemicryptophytes had a larger amount in six life forms, accounting for 31.25% of the total. H. davidii community had the typical life form characteristics of temperate steppe.

Morfo-anatomia do desenvolvimento de celtis iguanaea (jacq.) sarg. (ulmaceae) submetida ao alagamento e à submersão / Developmental morphology and anatomy of celtis iguanaea (jacq.) sarg. (ulmaceae) submitted to flooding and submersion

Celtis iguanaea es una especie pionera de la vegetación rebaliera. Las plantas de esta especie que ocurren en la planicie de inundación, con el eófilo completamente extendido, fueron sometidas a los siguientes tratamientos: capacidad de campo, anegadas por 25, 50 y 75 días y sumergidas por 25 y 50 días. Se constató que el anegamiento y la sumersión inhiben el crecimiento de las plantas causando una disminución de la materia seca de la parte aérea y la raíz. Plantas hundidas también presentaron abscisión foliar, degeneración del sistema radicular y un proceso precoz de senescencia. Después de 50 días de sumersión, todas las plantas murieron. Las plantas anegadas y sumergidas presentaron crecimiento secundario reducido de la raíz, hipocótilo y epicótilo. Las plantas anegadas por 75 días presentaron lenticelas y mayor número de pelos absorbentes. Los cotiledones y eófilo de las plantas anegadas y sumergidas no presentaron alteraciones anatómicas evidentes. El porcentaje de espacios intercelulares tampoco fue alterado. Celtis iguanaea, al presentar algunos caracteres que posiblemente se adapten a las condiciones de saturación hídrica del suelo, puede ser considerada como planta intolerante del anegamiento y la sumersión por un largo período.

Celtis iguanaea is a pioneer species of ciliary forest. In order to elucidate aspects of tolerance to the flooding andthe submersion, plants were submitted to the following treatments: field capacity, flooded for 25, 50 and 75 days and submerged by 25 and 50 days. It was verified that the flooding and the submersion inhibit the growth of the plants (decrease of the dry weight of the aerial part and root). Plants submerged also presented chlorosis, leaf abscission, degeneration of the root system and precocious senescence. After 50 days of submersion, all the plants died. Submerged and flooded plants presented reduced secondary growth of the root, hipocotyl and epicotyl. Flooded plants for 75 days presented lenticels and larger number of absorbent hairs. Cotyledons and eophylls of the flooded and submerged plants did not present evident anatomical alterations. Percentage of intercellular spaces in the root cortex was also not altered. Celtis iguanaea can be considered as intolerant plant to the flooding and the submersion, for long period.