The showy and the shy

Ptilotus gaudichaudii
Fig. 1. An inflorescence of Ptilotus gaudichaudii, showing open flowers. Photo by T. Hammer.

In my recent paper (Hammer et al., 2018), two species were reinstated from Ptilotus gaudichaudii (Steud.) J.M.Black (Amaranthaceae), Ptilotus eremita (S.Moore) T.Hammer & R.W.Davis and Ptilotus modestus T.Hammer. These species were previously included as subspecies under P. gaudichaudii, namely subspp. parviflorus (Benth.) Lally and eremita (S.Moore) Lally. The paper includes the taxonomic and nomenclatural histories of the species, including the justification for raising them to species rank.

This study was spurred by observations made in the field, particularly the species P. eremita and P. gaudichaudii, which overlap significantly in their distributions and were found co-occurring at several sites without any intermediates. The species boundaries within this group was assessed by examining the morphology of specimens from throughout their ranges.

Ptilotus eremita
Fig. 2. An inflorescence of Ptilotus eremita, showing an open flower (centre). Photo by T. Hammer.

Ptilotus gaudichaudii can be reliably discriminated from the other two species by having larger tepals (technically sepals), style, staminal filaments and anthers and having widely-gaping showy flowers (Fig. 1). Ptilotus eremita by comparison has flowers which do not gape widely after anthesis, and instead form a tube down to to the ovary (Fig. 2). The small stamens crowd the pistil and do not orientate themselves in the way observed for P. gaudichaudii. Ptilotus modestus is most similar to P. eremita, but the latter varies from the former by having a slightly longer style and staminal filaments and having three fertile stamens (as opposed to four) and occurring in central and eastern Australia (as opposed to Western Australia). Read more about this study here:

Hammer, T.A., Davis, R.W. & Thiele, K.R. (2018). The showy and the shy: reinstatement of two species from Ptilotus gaudichaudii (Amaranthaceae). Australian Systematic Botany 31: 1–7.

Ptilotus benlii

Ptilotus benlii
Flowering inflorescences of Ptilotus benlii. Photo by R. Davis.

Ptilotus benlii R.W.Davis & T.Hammer was recently described in the journal Nuytsia as a new species for Western Australia (Davis & Hammer, 2017). It is a perennial herb found from south of Kalbarri to north of Merridin, WA.

Ptilotus benlii is closely related to P. calostachyus F.Muell., P. drummondii (Moq.) F.Muell., P. aphyllus Benl and P. schwartzii (F.Muell.) Tate. It shares the character with these species of possessing staminal cup appendages, but can be easily differentiated by its larger, green-white flowering spikes and bright pink filaments and stamens. Ptilotus benlii is also quite close to the southwestern species P. esquamatus (Benth.) F.Muell., with which it differs in that the latter lacks staminal cup appendages and has much smaller inflorescences of pinkish flowers and a decumbent habit.

Ptilotus benlii
The habit of Ptilotus benlii. Photo by R. Davis.

The species was named in honour of German botanist Gerhard Benl (1910–2001), who contributed significantly to the taxonomy of Ptilotus throughout his career, naming upwards of 30 species and various infraspecific taxa.

Davis, R.W. & Hammer, T.A. (2017). Ptilotus benlii (Amaranthaceae), a new species from Western Australia. Nuytsia 28: 299–302.