Thaumatophyllum petraeum (Chodat & Vischer) Sakur., Calazans & Mayo, 2018

Sakuragui, Cassia Monica, Calazans, Luana Silva Braucks, Oliveira, Leticia Loss de, Morais, Erica Barroso de, Benko-Iseppon, Ana Maria, Vasconcelos, Santelmo, Schrago, Carlos Eduardo Guerra & Mayo, Simon Joseph, 2018, Recognition of the genus Thaumatophyllum Schott - formerly Philodendron subg. Meconostigma (Araceae) - based on molecular and morphological evidence, PhytoKeys 98, pp. 51-71 : 59-60

Thaumatophyllum petraeum (Chodat & Vischer) Sakur., Calazans & Mayo comb. nov. Fig. 4.

Philodendron petraeum Chodat & Vischer, Bull. Soc. Bot. Genève 11: 296. 1919 publ. 1920.

Philodendron petraeum Type. Paraguay, Tobaty between Tobaty and Barrero Grande, R.H. Chodat & W. Vischer 349 (holotype: G).

Philodendron petraeum Philodendron petraeum var. triangulare Chodat & Vischer, Bull. Soc. Bot. Genève 11: 299. 1919 publ. 1920.

Philodendron petraeum Type. Paraguay, Tobaty between Tobaty and Barrero Grande, R.H. Chodat & W. Vischer 347 (holotype: G).

Philodendron petraeum var. valenzuelae Chodat & Vischer, Bull. Soc. Bot. Genève 11: 299. 1919 publ. 1920.

Philodendron petraeum Type. Paraguay, prope Valenzuela, R. H. Chodat & W. Vischer 357 (holotype: G).

Remarks.

The species was previously synonymised under P. tweedieanum (= T. tweedieanum ) by Croat and Mount (1988). We propose its reinstatement as an accepted species based on the following morphological differences: herbs erect and rupiculous (x herbs decumbent or rhizomatous subterranean acaulous in T. tweedieanum ), prophyll deciduous when still herbaceous (x marcescent and persistent-membranous in T. tweedieanum ), denudation of posterior division absent (x present in T. tweedieanum ), presence of stylar central dome in pistillate flowers (x absence of stylar central dome in T. tweedieanum ). Besides having a different gynoecium type ( Calazans et al. 2014), the majority-rule consensus tree based on morphological characters support these species as different lineages. Furthermore, the phylogeny based on molecular characters supports the two species as separate taxa ( Loss-Oliveira et al. 2014). Thaumatophyllum petraeum was first described for Paraguay with four varieties and are still recorded only from this country. We have no evidence to recognise the varieties as distinct taxa, except for. P. petraeum var. tobatiense Chodat & Vischer, which is a synonymous of P. undulatum (= T. undulatum ).

Figures

Figure 4. Thaumathophyllum petreum. A Habit B Longitudinal cut of the inflorescence C Staminode D Stamen E Longitudinal cut of a female flower F Transversal cut of a female flower showing the 6 - locular ovary G Side view of a female flower H Infructescence. All from Calazans & Morais 28 (RB).