Croton pycnocephalus Baillon (1864: 356)

Pereira, Amanda Da Paixão Noronha, Riina, Ricarda & Caruzo, Maria Beatriz Rossi, 2022, Croton (Euphorbiaceae) of the Brazilian state of Paraná: an annotated checklist, species distribution, and identification key, Phytotaxa 570 (3), pp. 231-274 : 256

27. Croton pycnocephalus Baillon (1864: 356) .

Type: — BRAZIL. Rio Grande do Sul: 1864, C. Gaudichaud-Beaupré 1668 (holotype P 06773116 !; isotype A 00257986!). ( Fig. 15 , C–D)

This shrub can be distinguished by the indument of stipitate stellate trichomes distributed throughout the plant, small leaves (up to 1.5 cm long), and staminate petals that are twice the size of the sepals. Due to its small leaves and twice bifid styles, C. pycnocephalus is commonly confused with C. serpyllifolius and C. chamaepitis , however, several vegetative characteristics distinguish it from both species ( Table 1 ). The species belongs to section Lamprocroton subsect. Argentini ( van Ee & Berry 2011) .

Distribution and habitat:— It occurs in southern Brazil (PR, RS) ( Caruzo et al. 2020), where it grows in sandy or rocky soils of ‘cerrado’, between 800 and 995 m elevation. ( Fig. 14 ).

Phenology:— Flowering and fruiting from October to February, and April to June.

Representative specimens:— PARANÁ: Balsa Nova, São Luiz do Purunã , 05 October 2001, J. M . Silva & O. S . Ribas 3473 ( MBM); idem, 21 April 2010, R . Ristow, L. J. B . Schip & W. T . Ferreira 609 ( IRAI, MBM). Jaguariaíva , Estrada do Sertão, entrada grande, 04 December 1964, G . Hatschbach 11967 ( K, MBM, UPCB); Vale do Codó , 12 October 2006, J. M . Silva, E . Barbosa & E. M . Cunha 5098 ( MBM, MG). Palmeira , Fazenda Padre Inácio, 30 May 1971, G . Hatschbach 26703 ( MBM) .

Figures

FIGURE 14. Map showing the known geographic distributions of Croton myrianthus, C. polygonoides, C. pycnocephalus, and C. reitzii in Paraná state.

FIGURE 15. Croton myrianthus. A. Branches with silvery leaves. B. Capsules. C. pycnocephalus. C. Inflorescence. D. Habit. C. sanctaecrucis. E. Inflorescence. F. Leaf with sessile nectary gland. G. Staminate flowers. H. Pistillate flowers with bifid styles. I. Capsules. C. salutaris. J. Cut in the bark showing red latex. K. Leaf with stipitate nectary glands. L. Urceolate pistillate flowers. Photos: A–I: A.P.N. Pereira, J, L: R. Riina, K: O.L.M. Silva.