@article {gottschling_testing_2004, title = {Testing hypotheses on disjunctions present in the primarily woody Boraginales: Ehretiaceae, Cordiaceae, and Heliotropiaceae, inferred from ITS1 sequence data}, journal = {Int. J. Plant Sci.}, volume = {165}, number = {4 Suppl.}, year = {2004}, pages = {S123{\textendash}S135}, abstract = {

Hypotheses on the origin of the current distribution patterns and bicontinental disjunctions of Cordiaceae, Ehretiaceae, and Heliotropiaceae (Primarily Woody Boraginales) are tested by pairwise comparison of Kimura two-parameter distances. Estimated absolute dates of fossils and geological events (plate tectonics, climate changes) were used to calibrate a molecular clock. A mid-Cretaceous origin of the Primarily Woody Boraginales is proposed with an initial diversification in South America. Plate tectonics appear to play a minor role in their phylogeography. Most disjunctions are best explained by the rare events of long-distance dispersal because of the widespread occurrence of drupaceous fruits and their potential for endozoochoria. Furthermore, migrations and extinctions might have played a considerable role in the formation of the current distribution patterns.

}, keywords = {{ITS1}, distribution, divergence rate, Kimura two-parameter distances, long-distance dispersal, paleoclimate, phylogeography, vicariance.}, author = {Marc Gottschling and Diane, N and HH Hilger and M. Weigend} } @article {diane_transfer_2002, title = {Transfer cells in the seeds of Boraginales}, journal = {Bot. J. Linn. Soc.}, volume = {140}, number = {2}, year = {2002}, pages = {155{\textendash}164}, abstract = {

The presence of transfer cells (TCs) in the seeds of Boraginales (Boraginaceae s.s., Hydrophyllaceae, Heliotropiaceae, Ehretiaceae, Cordiaceae and Lennoaceae) has been reported but has not hitherto been studied systematically. This study, surveying the seed anatomy of 50 species of Boraginales, demonstrates that in Heliotropiaceae, Cordiaceae, Ehretiaceae and Lennoaceae, TCs are found in an uninterrupted course from the placenta via the funicle to the seed coat. These families are characterized by indehiscent fruits with a protective endocarp. The TCs may act as a sponge, thus promoting rapid germination when sufficient water is available. In Hydrophyllaceae, which have capsular fruits, TCs are often found but have a different structure and are restricted to the seed coat. Boraginaceae s.s. on the other hand are characterized by a complete absence of TCs in their seeds. The presence of TCs in seeds is considered as a synapomorphic trait and appears to be phylogenetically informative.

}, author = {Diane, N and Hilger, HH and Gottschling, M} } @article {diane_leaf_????, title = {Leaf anatomy and foliar trichomes in Heliotropiaceae and their systematic relevance}, journal = {Flora}, volume = {198}, number = {6}, year = {2003}, pages = {468{\textendash}485}, author = {Diane, N and Jacob, C and HH Hilger} } @article {hilger_systematic_2003, title = {A systematic analysis of Heliotropiaceae (Boraginales) based on trnL and ITS1 sequence data}, journal = {Bot. Jahrb. Syst.}, volume = {125}, number = {1}, year = {2003}, pages = {19{\textendash}51}, abstract = {

The infrafamilial relationships of Heliotropiaceae (Boraginaceae subfam. Heliotropioideae according to traditional systems) are reevaluated using molecular data of nuclear ITS1 (86 species) and plastidal trn LUAA intron (66 species) sequences. The results obtained from our investigations show that traditional generic limits warrant adjustment. Heliotropiaceae fall into two large clades. The first clade includes, in basal position, the genus Ixorhea . The genus Myriopus (formerly Tournefortia sect. Cyphocyema) is sister to Euploca (formerly Hilgeria, Schleidenia, Heliotropium sect. Orthostachys). The remaining sections of Heliotropium, Tournefortia sect. Tournefortia and the three small genera Argusia, Ceballosia, and Nogalia, segregated from Heliotropium, constitute the second large clade. Argusia, Ceballosia, and Nogalia cluster within clades of Heliotropium and therefore are reincluded in this genus. Within Heliotropium, the species of former Tournefortia sect. Tournefortia represent a lineage of tropical New World Heliotropium species, growing in humid environments, whereas all other Heliotropium species are found in semi-arid habitats. Before new combinations in the genus Heliotropium are made for \"Tournefortia\", the exact relationship within New World Heliotropium needs to be resolved, and a revision of \"Tournefortia\" is inevitable. We advocate maintaining the genus Tournefortia, which is easily defined, and we conclude that under this definition the genus Heliotropium is paraphyletic. Five genera are thus accepted; 22 new combinations within Heliotropiaceae are presented.

}, author = {Hilger, HH and Diane, N} }