Invading exotic plants are thought to succeed primarily because they have escaped their natural enemies, not because of novel interactions with their new neighbors. However, we find that Centaurea diffusa, a noxious weed in North America, has much stronger negative effects on grass species from North America than on closely related grass species from communities to which Centaurea is native. Ce...

A new species, Kosteletzkya rotundalata, is described from northeastern Democratic Republic of the Congo. A second species, K. borkouana, originally characterized as endemic to northern Chad, is here documented from several localities in the Albertine Rift of eastern Democratic Republic of the Congo.

Five new records of terrestrial and lithophytic orchid species were gathered from Penang Hill, Pulau Pinang, Malaysia namely Bulbophyllum depressum, Goodyera pusilla, Peristylus monticola, Podochilus microphyllus, and Zeuxine gracilis. Checklist of each species is provided and their distribution in Penang Hill is discussed.

Eight sesquiterpene lactones were isolated from Centaurea solstitialis (yellow starthistle). They are solstitialin A, repin, subluteolide, acroptilin, janerin, cynaropicrin, and the new &tones solstitiolide and episolstitiolide.

These paper deals with 45 taxa, seven of which are new to the Balearic Islands flora: Agrostis capillaris L., Centaurea solstitialis L. Chenopodium strictum Roth, Datura wrigthii Regel, Kickxia elatine (L.) Dumort. subsp. elatine, Ranunculus xatardii Lapeyr. and Senecio inaequidens DC. On the other hand, six taxa [Catananche caerulea L., Centaurea apula Lam., Filago micropodioides Lange, Legous...

In the search for new sources of sesquiterpene lactones, six Centaurea species have been analyzed. The activity against the fungus Cunninghamella echinulata of (+)-cnicin (1) and (+)-salonitenolide (2), isolated from the Centaurea plants, as well as that of (+)-costunolide (3), (-)-dehydrocostuslactone (4), (-)-lychnopholide (5) and (-)-eremantholide C (6), has been evaluated. Compounds 3 and 4...

Human modification of the environment is causing both loss of species and changes in resource availability. While studies have examined how species loss at the local level can influence invasion resistance, interactions between species loss and other components of environmental change remain poorly studied. In particular, the manner in which native diversity interacts with resource availability...