A new fern-feeding aphid species, Micromyzusplatycerii, collected in Sakaerat Research Station in Thailand, is described.

Fern gametophytes and young sporophytes often provide too little material for DNA extraction and are particularly difficult to identify to genus. Here we developed an efficient procedure called 'Tissue-direct PCR', in which a slice of fern tissue is mixed with PCR reagents and primers, allowing certain genomic regions to be amplified directly in the thermal cycler. For these diminutive and feat...

Certain fatty acids in the C(5) to C(18) range, at concentrations as low as 10(-5) M, were found to inhibit the germinations of spores of the sensitive fern, Onoclea sensibilis L. The addition of gametophytic culture flltrates of the bracken fern, Pteridium aquilinum (L.) Kuhn, containing antheridogen A, was found to overcome this inhibition and allow the spores to germinate and the gametophyte...

citation: Choberka, E.G., M.R. Penskar, and P.J. Higman. 2001. Special plant abstract for Gymnocarpium robertianum (limestone oak fern). Michigan Natural Features Inventory, Lansing, MI. 2 pp. fern and lacks the pronounced, extended tips of the main leaf segments so evident in well-developed fronds of G. robertianum. Best survey time/phenology: Gymnocarpium robertianum is recognizable whenever ...

An affine transformation on the plane is a mapping T that preserves collinearity and ratios of distances: given two points A and B, if C is the middle of the segment [A,B] then T (C) is the middle of the segment [T (A), T (B)]. Translations, contractions, expansions, reflections, rotations, are all particular cases of affine transformations. In general, an affine transformation T maps a point (...