Newly discovered tetraploid Fagopyrum homotropicum in Tibet, China

A cryptic species of Fagopyrum (Polygonaceae), F. homotropicum, is described and illustrated from Mangkang county, Tibet, China. F. homotropicum was firstly discovered in the 90’s, being to be diploid and characterized being a self-pollinating taxon. Detailed information of F. homotropiucm was rarely reported. In this paper, we summarized the morphological and karyological characters of tetraploid form F. homotropiucm (2n=4x=32), it is self-pollinating, and morphology indistinguishable in comparison from the diploid form.

Pellaea zygophylla, a new combination for a distinctive & well-known but neglected fern.

Pellaea ovata is a widespread species, sexual diploid in Texas & northeastern Mexico but an apogamous triploid in northwestern Mexico, south to northern Argentina, & on Hispaniola. The type belongs to the southern, apogamous triploid form. Although these two forms have been discussed repeatedly in the literature, morphological distinctions between them have been overlooked and they have not been recognized taxonomically. However, they are distinct. Pellaea ovata s.s. has puberulent rachides & costae; pinnae usually 2-pinnate with a well-defined main axis & pinnules borne singly; fertile pinnules ovate, cordate basally & rounded apically. The sexual diploid form has rachides & costae glabrous; pinnae pseudo-dichotomously branched & pinnules usually paired; fertile pinnules narrowly rounded-trapeziform, obliquely truncate to cordate basally & truncate apically. Riddell named the sexual diploid form Pteris zygophylla, from which I give it the new combination Pellaea zygophylla.

Pellaea zygophylla, a new combination for a distinctive & well-known but neglected fern

Pellaea ovata is a widespread species, sexual diploid in Texas &northeastern Mexico but an apogamous triploid in northwestern Mexico, south to northern Argentina, &on Hispaniola. The type belongs to the southern, apogamous triploid form. Although these two forms have been discussed repeatedly in the literature, morphological distinctions between them have been overlooked and they have not been recognized taxonomically. However, they are distinct. Pellaea ovata s.s. has puberulent rachides & costae; pinnae usually 2-pinnate with a well-defined main axis &pinnules borne singly; fertile pinnules ovate, cordate basally &rounded apically. The sexual diploid form has rachides &costae glabrous; pinnae pseudo-dichotomously branched &pinnules usually paired; fertile pinnules narrowly rounded-trapeziform, obliquely truncate to cordate basally &truncate apically. Riddell named the sexual diploid form Pteris zygophylla, from which I give it the new combination Pellaea zygophylla.

Width and surface of leaf blades of Lolium multiflorum Lam.

Differences in the shape of ribs can be observed in transverse sections of leaf blades of Italian ryegrass (<i>Lolium multiflorum</i> Lam.) var. 'Szelejewska', a diploid, has ribs similar to triangles, and 'Kroto', a tetraploid, has ribs which are more rounded, dome-like. A coefficient expressing width and surface increase of the leaf blade in relation to unribbed leaves has been determined. This coefficient (W) was calculated from the ratio of upper, wavy part of the leaf blade (g), to its width W=g/l. For Italian ryegrass the coefficient is from 1.5-1.46 and thus the width and the surface of the upper leaf blade is increased on the average by about 30%. With basic fertilization (1N) this coefficient is smaller for the diploid form as compared to the tetraploid. An increased dose of nitrogen (3N) causes increase of the coefficient in the diploid and a decrease in the tetraploid. Thus the joint action of the variety and fertilization in respect to the examined character is not equally significant to the two varieties.

Suitability and Feeding Preference of Selected North American, European, and Asian Elm (Ulmus spp.) Biotypes to Elm Leaf Beetle (Coleoptera: Chrysomelidae)

Recently introduced North American elm cultivars, simple and complex elm hybrids of European and Asian parentage, and simple Asian hybrids of U. pumila and U. japonica parentage growing at The Morton Arboretum, Lisle, IL, were evaluated in laboratory bioassays for ovipositional response, and feeding preference and suitability for larvae and adults of the elm leaf beetle, Xanthogaleruca luteola (Muller). Larval and adult no-choice and adult multiple-choice feeding studies revealed that the North American cultivars of U. americana ‘Jefferson’ and U. americana ‘Valley Forge’, U. americana (diploid form), and U. americana were the least preferred for feeding and reproduction by the elm leaf beetle. Among simple and complex European hybrids, ‘Homestead’, ‘Patriot’, and ‘Prospector’ were least preferred and least suitable for larval development, feeding, and reproduction by adult elm leaf beetles. Hybrids of ‘Frontier’, ‘Pioneer’, and ‘Regal’; the simple Asian hybrids of ‘Cathedral’ and ‘New Horizon’; and U. pumila were more highly preferred for feeding and suitable for reproduction. The least preferred and least suitable North American biotypes of U. x americana ‘Jefferson’, U. americana ‘Valley Forge’, and U. americana (diploid form), simple and complex European hybrids of ‘Homestead’, ‘Patriot’, and ‘Prospector’, show promise for use in areas where the elm leaf beetle is persistent and for future elm breeding programs.

CHROMOSOME NUMBERS OF PERENNIAL Bromus SPECIES COLLECTED IN THE USSR

The chromosome number of accessions of Bromus inermis was 2n = 56 except for those from Chimkent which had 2n = 28, A diploid form (2n = 14) was also found near Chimkent and it is of importance because of its possible relationship to B. inermis or B. riparius. The accessions labelled as B. riparius were 2n = 70. Two accessions of B. benekenii had 2n = 28. The significance of several of these accessions is discussed briefly.Key words: Chromosome number, Bromus, perennial, tetraploid, diploid