"A set of 40 drawings and accompanying etchings of mostly African Erica species is referred to as Ericetum africanum of A. van Royen. The original drawings are at L [Leiden] ... The etchings are marked "P. Cattell: del." and "J: v: d: Spyk fecit", the set of etchings at L has no no. 11 but lacks 16. Corrections in the handwriting of A. van Royen show that this was a series of proofs. The original herbarium specimens in the herb. van Royen (L) of circa 30 plates have been traced. The drawings follow the specimens closely.... Another set of etchings is reported from BM(NH) [British Museum, Natural History].--Cf. Stafleu.

Plates are not labeled or numbered.

Stafleu and Cowan (2nd ed.) Royen composite works (2)

Pritzel (2nd ed.) 7844