Eocene “Chusquea” fossil from Patagonia is a conifer, not a bamboo

Chusquea oxyphylla Freng. & Parodi, 1941, a fossilized leafy branch from the early Eocene (52 Ma), late-Gondwanan Laguna del Hunco biota of southern Argentina, is still cited as the oldest potential bamboo fossil and as evidence for a Gondwanan origin of bamboos. On recent examination, the holotype specimen was found to lack any typical bamboo characters such as nodes, sheaths, ligules, pseudopetioles, or parallel leaf venation. Instead, it has decurrent, clasping, univeined, heterofacially twisted leaves with thickened, central-longitudinal bands of presumed transfusion tissue. These and other features allow confident placement in the living Neotropical and West Pacific disjunct genus Retrophyllum (Podocarpaceae), which was recently described from the same fossil site based on abundant, well-preserved material. However, the 1941 fossil holds nomenclatural priority, requiring the new combination Retrophyllum oxyphyllum (Freng. & Parodi) Wilf, comb. nov. No reliable bamboo fossils remain from Gondwana, and the oldest South American bamboo fossils are Pliocene. Chusquea joins a growing list of living New World genera that are no longer included in Paleogene Patagonian floras, whose extant relatives are primarily concentrated in Australasia and Malesia via the ancient Gondwanan route through Antarctica.

The history of Mandragora turkomanica (Solanaceae)

In 1938 a new species, Mandragora turcomanica O. Mizgir., was discovered in the Sumbar river valley near the Soviet–Iranian border in the nowadays Republic of Turkmenistan. The prevailing hypothesis of its origin was that M. turcomanica is a species that survived in a refuge between the Mediterranean and Himalayan parts of the now disjunct genus range. Meteorological observation conducted by the author in the area occupied by the species revealed that the presumed high frost tolerance of the species was exaggerated. The plants of the Sumbar Valley could survive only in a narrow altitude belt due a very specific combination of favorable microclimate and soil. However, the present distribution of mandrake plants in Turkmenistan cannot explain why the plants were never observed in the southern valleys of the Turkmen–Khorasan range of northern Iran, which has a similar landscape to the Sumbar Valley and a considerably warmer climate. Cultivation and usage of the Turkmenian mandrake as a medicinal plant in Iran, its name “halom” and the fact that all known locations of Turkmenian mandrake match the traces of ancient irrigation in the Sumbar Valley support the hypothesis that Turkmenian mandrake could be the holy plant the ancient Iranians called “Haoma”, repeatedly mentioned in the “Avesta” (the collection of sacred texts of the ancient Aryan religion known as Zoroastrianism). The introduction of mandrake currently growing in Sumbar Valley from the other region is supported by the species biology, i.e. the lack of dispersal of its fruits by birds which strongly limits its potential distribution, and by a recently reported high genetic similarity of Turkmenian mandrake with plants from Israel.

Is Ronnbergia (Bromeliaceae, Bromelioideae) a geographically disjunct genus? Evidence from morphology and chloroplast DNA sequence data

A phylogenetic study testing the monophyly of the geographically disjunct genus Ronnbergia (Bromeliaceae, Bromelioideae) is presented. The phylogenetic analyses were based on taxon sampling that included all but one species of Ronnbergia, and representative lineages across the subfamily Bromelioideae. Three chloroplast DNA sequence markers (matK, psbA-trnH, and trnL-trnF) and morphological data were used for the phylogenetic reconstruction. Both the molecular and morphological datasets supported the polyphyly of Ronnbergia, either independently or in combination. These findings suggest that the geographic disjunction of this genus is most likely a product of taxonomic misinterpretation. The results also indicate that the species currently circumscribed in Ronnbergia are closely related to species in the genus Aechmea with similar geographic ranges. The datasets do not have enough resolution power to reconstruct a deep phylogenetic history that involves all the species of Ronnbergia. Nevertheless, this study provides clues for future approaches that should focus on a larger species sampling and the use of multi-locus DNA sequence data.