Quantitative characters of Central European wild roses (Rosaceae: Rosa) and their applicability for determination

Abstract

An example reveals, that the classification of a character as measurable or not can depend on the effort of investigation. An overview on measurable characters treated in the literature about central European wild roses (Rosaceae: Rosa) from 1820 to the present is given. Many of these characters are better collected in ordinal and not in metric scales. For 8 characters estimated as suitable for measurement, own observations and investigations are presented. Some error sources (most of them in the objects, one in the mind of the observer) must be noted. When measuring characters of the hips and their stalks, it is necessary to consider the dimorphism between the central and lateral fruits of the inflorescence. The restriction of measurements on hips of solitary flowers reduces the scattering of measure. The same effect has the use of standard deviation instead of the variation. Caused by an optical illusion, the length of the stalk in relation to the length of the hip is mostly overestimated. Quantitative analysis of the following characters seems to be useful to gain data for the diagnosis of rose species: mainly the pedicel length in relation to the hip length and the orifice diameter; secondly the length of the terminal leaflet, the length-width index of it and the petal length.