Home at Last II: Gerbera hieracioides (Kunth) Zardini (Mutisieae, Asteraceae) is really a Chaptalia.

Xiaodan Xu,Vicki A Funk,Jun Wen,Wei Zheng

doi:10.3897/phytokeys.95.22916

Abstract

Gerbera hieracioides (Kunth) Zardini of the Gerbera-complex (Mutisieae, Asteraceae/Compositae) is distributed in Ecuador and Peru. This perennial herb was first named as Onoseris hieracioides Kunth and was later recognised as Trichocline hieracioides (Kunth) Ferreyra. Now it is generally treated as Gerbera hieracioides (Kunth) Zardini but it has never been included in any section of Gerbera. In this study, the position of Gerbera hieracioides is assessed based on morphology and a molecular phylogeny that includes G. hieracioides and 28 other species from the Gerbera-complex. Morphologically, G. hieracioides bears leaves with the adaxial epidermal surface without stomates but with soft thin trichomes, bracteate scapes, trimorphic capitula and inner ray florets with the corolla shorter than the style. These characters suggest that the species is most closely related to Chaptalia rather than to Gerbera or Trichocline. Furthermore, the phylogenetic results based on two nuclear (ITS and ETS) and two chloroplast (trnL–trnF and trnL–rpl32) sequences strongly support the placement of G. hieracioides nested within Chaptalia. As both morphological characters and the molecular phylogenetic results support the transfer of G. hieracioides to Chaptalia, this enigmatic taxon is recognised as Chaptalia hieracioides (Kunth) X.-D. Xu & W. Zheng.

Highlights

Gerbera hieracioides (Kunth) Zardini (Mutisieae, Asteraceae) is a species belonging to the Gerbera-complex (Gerbera L., Leibnitzia Cass., Uechtritzia Freyn, Amblysperma Benth., Chaptalia Vent., Trichocline Cass., Perdicium L. and Lulia Zardini)
Katinas (2004) presented a key to distinguish the genera of the Gerbera-complex and Gerbera and Chaptalia were found to share the same trait of achenes rostrate at the apex but this is not found in Trichocline
The characters of leaf adaxial epidermis of G. hieracioides including the lack of stomates and the presence of soft thin trichomes, as well as bracteate scapes and cell shape and striations, all suggest that the species is closest to Chaptalia

Summary

Introduction

Gerbera hieracioides (Kunth) Zardini (Mutisieae, Asteraceae) is a species belonging to the Gerbera-complex (Gerbera L., Leibnitzia Cass., Uechtritzia Freyn, Amblysperma Benth., Chaptalia Vent., Trichocline Cass., Perdicium L. and Lulia Zardini). The species is distributed in Ecuador and Peru. This perennial herb was first named as Onoseris hieracioides Kunth in 1818. It was transferred to Trichocline hieracioides (Kunth) Ferreyra in 1944. The apex of achenes is truncate in Trichocline but tapering or beaked in G. hieracioides (Zardini 1974, Hansen 1990). Zardini (1974, 1975) moved it into Gerbera because it had bracteate scapes, uniseriate ray florets, achenes rostrate at the apex and slender achene hairs. Gerbera and Chaptalia were found to share the same traits such as achenes rostrate at the apex (Katinas 2004) and the transfer of Trichocline hieracioides to Gerbera remained controversial (Hansen 2006)

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Conclusion