Helichrysum decorum DC, Helichrysum lepidissimum S. Moore, and Helichrysum umbraculigerum are three species traditionally used in the South African medicine. The present work deals with the investigation of the spontaneous emission and the essential oils obtained from these plants cultivated in open field under uniform conditions. Fractions of the volatile organic compounds of the three species were rich in monoterpene hydrocarbons, representing more than 70% of the total composition. Pinene isomers were the most representative compounds: β-pinene in H. decorum (53.0%), and α-pinene in H. lepidissimum (67.9%) and H. umbraculigerum (54.8%). These latter two species evidenced an important amount of sesquiterpene hydrocarbons (SH) especially represented by γ-curcumene ( H. lepidissimum ) and α- and β-selinene ( H. umbraculigerum ). On the contrary, in the EOs, sesquiterpenes compounds prevailed, representing more than 64% of the identified fraction to reach more than 82 and 87% in H. umbraculigerum and H. lepidissimum, respectively. Although the chemical classes and their relative abundances were comparable among the three species, the individual compounds of EOs showed large differences. In fact, caryophyllene oxide (26.7%) and γ-curcumene (17.4%) were the main constituents in H. decorum , and H. lepidissimum respectively, while neo -intermedeol (11.2%) and viridiflorol (10.6%) characterized H. umbraculigerum .

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The first comprehensive plant checklist for the Bvumba massif, situated in the Manica Highlands along the Zimbabwe-Mozambique border, is presented. Although covering only 276 km 2 , the flora is rich with 1250 taxa (1127 native taxa and 123 naturalised introductions). There is a high proportion of Orchidaceae and Pteridophyta, with both groups showing a higher richness than for adjacent montane areas, which may be due to the massif's relatively high moisture levels as a result of frequent cloud cover. However, in contrast to other mesic montane regions in southern Africa, there are relatively few near-endemic or range-restricted taxa: there is only one local endemic, Aeranthes africana , an epiphytic forest orchid. This is likely to be an effect of the massif having limited natural grassland compared to forest, the former being the most endemic-rich habitat in southern African mountains outside of the Fynbos Biome. Six other near-endemic taxa with limited distribution in this portion of the Manica Highlands are highlighted. The high number of invasive species is probably a result of diverse human activities in the area. The main species of concern are Acacia melanoxylon , a tree that is invading grassland and previously cultivated land, the forest herb Hedychium gardnerianum which in places is transforming forest understorey with an adverse effect on some forest birds, and the woody herb Vernonanthura polyanthes which invades cleared forest areas after fire. Future botanical work in the massif should focus on a more detailed exploration of the poorly known Serra Vumba on the Mozambican side and on the drier western slopes. This will allow for a more detailed analysis of patterns of endemism across the Manica Highlands.

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