No abstract

Field and laboratory studies of 19 diclinous species endemic to Australia help to clarify the nature and evolution of andromonoecy, androdioecy, and dioecy in the genus Solanum. Ten species are andromonoecious; typically these species bear inflorescences with a single, large basal hermaphroditic flower and 12-60 distal, smaller staminate flowers. We suggest that the andromonoecious condition was derived from hermaphroditic-flowered ancestors in part by hemisterilization of flowers but largely by addition of staminate flowers. The resultant larger inflorescences are hypothesized to serve both to attract and to entrain pollinators, yielding more or higher-quality seed set in hermaphroditic flowers and/or greater dispersion of pollen from staminate flowers. We suggest that andromonoecy may also serve to reduce selling. Nine other species are morphologically androdioecious but functionally dioecious. In these species, staminate flowers, like those of the andromonoecious species, bear anthers with copious tricolporate pollen and a highly reduced gynoecium. The morphologically hermaphroditic flowers are functionally pistillate and borne singly in inflorescences, and they bear anthers with inaperturate pollen. The inaperturate pollen, although viable, never germinates and is hypothesized to be retained in pistillate flowers as a reward to pollinators in the nectarless Solanum flowers. All other species of Solanum studied with pollen dimorphism in which one pollen morph is inaperturate are also best treated as functionally dioecious. We conclude that there is no evidence for androdioecy in Solanum. A review of other families suggests that there is little support for this unusual breeding system in any other angiosperm group either. Preliminary analyses suggest that andromonoecy and dioecy are polyphyletic in Solanum. Furthermore, dioecy is as likely to have arisen from hermaphroditic as from andromonoecious ancestors.

Eighteen native insect species „e,e found n„ /lowers of 1H Solanum species in afield study in , 'we^ewreTordTo Solanum /lowers in Australia are reported Jar Braunsapis and Xylocopa (Anthoplioridae) . Leioproctus and Trigona (Apidae) Two species each of the pollen-collecting bees Amegilla (Anthoplioridae). lictidae), and Trigona are considered the most significant floral visitors. This conclusion is b disinhuhon. abundance, and behavior of the bees, and on the high percentage o/Solanum pollen in poller, are hypothesized to effect inter population outcross, v I rig.ma s pollination, and spe, ics „/ Nomia transmit pollen both within and

Exotic Rubus taxa in Australia have been revised following consultation with European and North American experts in Rubus, allied with studies of variation in patterns of DNA restriction fragments and morphology. Many of these taxa have names that are applied for the first time in Australia (prefaced with a †). The major focus of the work was the Rubus fruticosus L. aggregate and taxa of this aggregate covered here are R. anglocandicans A. Newton, R. cissburiensis W.C. Barton & Ridd., †R. echinatus Lindl., †R. erythrops Edees & A. Newton, R. laciniatus Willd., R. leightonii Lees ex Leight. †R. leucostachys Schleich. ex Sm., †R. phaeocarpus W.C.R. Watson, R. polyanthemus Lindeb., †R. riddelsdellii Rilstone, †R. rubritinctus W.C.R. Watson, R. ulmifolius Schott (including R. ulmifolius var. ulmifolius and †R. ulmifolius var. anoplothyrsus Sudre), and R. vestitus Weihe, along with two undescribed taxa, Rubus sp. Scott Creek (D.E. Symon 16504) and Rubus sp. Tasmania (J.R. Hosking 1551). Other naturalised taxa are R. alceifolius Poir., R. ellipticus Sm., R. idaeus L., †R. laudatus A. Berger, †R. loganobaccus L.H. Bailey, †R. philadelphicus Blanch., R. roribaccus (L.H. Bailey) Rydb. and R. rugosus Sm. Patterns of morphological and molecular variation among individuals of the R. fruticosus agg. in Australia were examined. In phenetic analyses based on examination of 137 herbarium specimens and 27 morphological characters, taxa showed varying degrees of separation. Some taxa, for example R. anglocandicans and the two varieties of R. ulmifolius, formed distinct groups in these analyses whereas there was considerable overlap among individuals of other species. Fifty M13/HaeIII DNA-banding patterns (phenotypes) were identified among 198 collections from the R. fruticosus agg. across Australia. Thirty-five DNA phenotypes were correlated with 15 taxa of the R. fruticosus agg.; the remaining 15 DNA types correlated poorly or were determined with only a moderate level of confidence. R. anglocandicans, R. echinatus, R. leightonii, R. leucostachys, R. sp. Tasmania, R. ulmifolius and R. vestitus had two or more DNA phenotypes whereas only one DNA phenotype was observed for the remaining eight taxa. Taxa that were more distinct with respect to their DNA phenotypes also tended to be more distinct with respect to morphology based on a Mantel matrix correlation test. Within taxa that were difficult to tell apart morphologically, those sharing the same DNA phenotype were considered members of the same Rubus taxon. These results are discussed in the context of the evolution and ecology of the R. fruticosus agg. in Australia and in relation to the incomplete taxonomy of Rubus in Europe and North America.

Kangaroo apples, subgenus Archaesolanum, are a unique and still poorly known group within the genus Solanum. Here we aimed to reveal phylogeny, historical biogeography and age of diversification of Archaesolanum. We sampled all recognized species of the group and sequenced three chloroplast regions, the trnT-trnL spacer, trnL intron and trnL-trnF spacer to calibrate a molecular clock to estimate the age of the group. Distributional data were combined with the results of phylogenetic analysis to track the historical processes responsible for the current range of the group. Our analysis supported the monophyly of the kangaroo apples and the biogeographical disjunction between the two subclades within the group. Based on the divergence time estimates the most recent common ancestor of kangaroo apples is from the late Miocene age (~9 MYA). Based on the age estimate the common ancestors of the kangaroo apples are presumed to have arrived in Australia by long-distance dispersal. The two distinct lineages within the group have separated during the aridification of the continent and further speciated in the brief resurgence of rainforests during the Pliocene.