N. P. Maslova

Classification of maximal subgroups of odd index in finite simple classical groups

The classification of maximal subgroups of odd index in finite simple classical groups is obtained.

A new taxon of staminate inflorescences Bogutchanthus gen. nov. (Hamamelidales) from the Paleocene of the Amur Region

Staminate inflorescences from the Paleocene deposits of the Amur Region (Russia) are described as a new genus, Bogutchanthus N. Maslova, Kodrul et Tekleva, on the basis of micromorphological characters. The inflorescences under description combine characters of the families Platanaceae and Hamamelidaceae (order Hamamelidales). Along with capitate inflorescences, tetramerous flowers with a differentiated perianth, and the presence of staminodes—typical characters of Cretaceous platanaceous plants—the new genus also shows some features that are known in extant and fossil members of the Hamamelidaceae: a loosely packed inflorescence, free stamens, secondarily bisporangiate stamens, crescent pollen sacs, and pantocolpate pollen grains. The inflorescences are associated with entire-margined leaves of the platanoid type.

New genus Sarbaicarpa gen. nov. (Hamamelidales) from the Cenomanian-Turonian of Western Kazakhstan

Anatomically preserved infructescences of Sarbaicarpa shilinii gen. et sp. nov. are described from the Cenomanian-Turonian of Kazakhstan and assigned to the Hamamelidales on the basis of their microstructure. The infructescence consists of about 30 free broadly cuneate fruits. The fruits are monocarpellate, without stylode, and basally with hairs. The seed is solitary and anatropic. Two types of sterile elements are present: (1) semispherical structures that are comparable in size to the fruits and densely covered with rounded trichomes and (2) narrow linear structures reaching more than a half of the fruit length. The new genus is characterized by a mosaic of platanaceous and hamamelidaceous characters. The plant remains are found associating with fossil leaves of the typically Platanus aspect.

Systematics of fossil platanoids and hamamelids

The data on fossil platanoids and hamamelids are generalized, their morphological diversity and probable patterns of the establishment of the extant families Platanaceae and Hamamelidaceae are analyzed. It is shown that morphological and epidermal characters of polymorphic leaves of typical platanoid appearance were formed in the Late Albian and remained essentially invariable to the present time, indicating the morphological stasis of these leaves combined with a wide variation range. In view of association with essentially different reproductive structures, it is proposed to classify these leaves by the morphological system irrespective of the natural system of angiosperms. A new system of extinct platanoids and hamamelids, which is based on reproductive structures and includes two orders, Hamamelidales and Sarbaicarpales ordo. nov., is proposed. Hamamelidales comprises two extant families, Platanaceae (with the subfamilies Platanoideae subfam. nov. and Gynoplatananthoideae subfam. nov.) and Hamamelidaceae, and the extinct family Bogutchanthaceae fam. nov.; the new extinct order Sarbaicarpales ordo. nov. consists of two new families, Sarbaicarpaceae fam. nov. and Kasicarpaceae fam. nov. In a system of flowering plants that is based on molecular data, the families Platanaceae and Hamamelidaceae are assigned to remote orders, excluding close relationship (APG, 2003). At the same time, the system of APG II often contradicts morphological and paleontological data, while traditional ideas of morphologists concerning the common origin of these families have recently been supported by paleobotanic evidence. Probable origin of the families Platanaceae and Hamamelidaceae from a common polymorphic ancestral group is discussed.

Infructescences of Friisicarpus sarbaensis sp. nov. (Platanaceae) from the Cenomanian-Turonian of western Kazakhstan

Platanoid capitate infructescences are described as a new species Friisicarpus sarbaensis. Infructescences of Friisicarpus N. Maslova et Herman have been first found in the Cretaceous of Kazakhstan. A joint burial of Friisicarpus infructescences and other platanoid reproductive structures as well as Platanus-like leaves are discussed. This indicates a considerable role of the group in the Cretaceous flora of Kazakhstan.

Liquidambar maomingensis sp. nov. (Altingiaceae) from the late Eocene of South China

UNLABELLED • PREMISE OF THE STUDY Phylogenetic analysis of DNA sequence data has changed our view on the evolution and systematics of plant taxa. Based on the phylogenetic analysis of several molecular markers, fruit anatomy, and pollen morphology, the genera Altingia and Semiliquidambar were formally transferred to the genus Liquidambar. The new species of Liquidambar from the Eocene of South China significantly extends our knowledge of the variability of the morphological characters of this genus in the geological past. Fossil leaves in conjunction with data on the associated reproductive structures allow us to make inferences about patterns in the evolutionary history of Liquidambar.• METHODS Fossil leaves and associated reproductive structures preserved as impressions were described and compared with the corresponding organs of extant and fossil relatives. The morphological variation of numerous leaves was examined by stereomicroscopy.• KEY RESULTS Liquidambar maomingensis sp. nov. is characterized by polymorphic leaves including both palmately lobed and unlobed leaves. This study presents the first observations of such dimorphism in the fossil record of Liquidambar leaves. Two distinct leaf groups are interpreted as sun and shade leaves.• CONCLUSIONS The fossil leaves and associated infructescences from Maoming probably belong to the same plant. The occurrence of fossil leaves similar to those of extant species previously considered within Semiliquidambar and Liquidambar with the associated infructescences close to those of Altingia provide paleobotanical evidence that justifies combining the genera Liquidambar, Altingia, and Semiliquidambar into the single genus Liquidambar as recently proposed based on molecular markers.

The new species Ettingshausenia sarbaensis (Angiospermae) from the Cenomanian-Turonian of Western Kazakhstan in light of the problem of classification of dispersed cretaceous Platanus-like leaves

Based on morphological and epidermal characters of the leaf, a new species, Ettingshausenia sarbaensis sp. nov., from the Cenomanian-Turonian of western Kazakhstan is described. In fossil Platanus-like leaves, the unique epidermal structure, with the combination of encyclocytic, laterocytic, and paracytic stomata and the presence of trichomes on one or from two to seven epidermal cells, is shown for the first time. Based on variations in morphological and epidermal characters, two morphotypes corresponding to groups of sun and shade leaves are recognized. The expediency of consideration of dispersed Cretaceous Platanus-like leaves within the framework of morphological classification of leaves is discussed.

Association of vegetative and reproductive organs of platanoids (Angiospermae): significance for systematics and phylogeny

Some examples of association between platanoid leaves and various reproductive structures are considered. The expediency of determining dispersed Cretaceous platanoid leaves using a morphological system that is independent of the system of modern plants is discussed. It is confirmed that leaf structures are more conservative than reproductive organs. It is proposed that, in the geological past, there was a polymorphic group that was probably represented by extinct families which gave rise to modern families (in particular, Platanaceae and Hamamelidaceae).

Phytopathology in fossil plants: New data, questions of classification

Examples of damages in fossil plants revealed using electron microscopy are considered. The formal classification of these damages is discussed.

Platimeliphyllum reznikoviorum N. Maslova, sp. nov. (Angiospermae) and associated infructescence from the Paleogene of central Kazakhstan

A new species Platimeliphyllum reznikoviorum N. Maslova is described from the Paleogene of Nizhnii Ashut locality (central Kazakhstan) based on the leaf macromorphological and epidermal characteristics. A capitate infructescence sharing characters of Platanaceae and some Hamamelidaceae was found together with the leaves. Small reticulate tricolpate pollen grains were found adhered to the carpel surface. The fossil leaves and reproductive structure are supposed to belong to the same plant. Fossil leaves attributed to Platimeliphyllum are associated with reproductive structures of various genera belonging to different families. Therefore we use the morphological classification for dispersed angiosperm leaves proposed by Krassilov (1979) to define the taxonomic position of this genus.