A checklist and macromorphological characterisation of Rosa L. (Rosaceae) in Jos, Plateau State, Nigeria

Abstract

Members of the genus Rosa L. have become well domesticated on the Jos Plateau due to its near temperate climate; yet, they have remained underexploited. It is necessary to document the existing varieties and types, as well as record differences in their external morphology for easy identification and proper utilization. Based on information provided at the office of the Plateau Horticultural Society as well as by prominent rosarians, gardens and nurseries were located and visited for consultation and data collection. Photographs of flowers and leaves were taken for comparison with those in rose monographs, catalogues and encyclopaedias so as to facilitate their recognition. Twenty-nine (29) rose varieties were encountered, including one (1) species-like rose, six (6) miniatures, six (6) old garden roses, nine (9) hybrid teas and seven (7) floribundas. Out of these, there were two (2) climbers, one (1) rambler, seven (7) small shrubs/miniatures and eighteen (18) shrubs. The key characters which differentiated the varieties were habit, length of flowering stem, number, size, presence or absence of prickles or thorns and their shapes, number of leaflets, number of flowers per stem, number of petals per flower, size of flower as well as presence or absence of hips. The high number of hybrids and the occurrence of representatives of all the classes of roses in the study area is an indication that the rose cut-flower industry may flourish on the Jos Plateau, Nigeria, if properly harnessed.