The Procellaria illustration can be found in George Edward’s recently published ornithology [Linnaeus refers to A natural history of uncommon birds], p. 80, tab. 90.
Linnaeus sends plants from seeds collected in Spain by the late Pehr Löfling, and sent to Linnaeus in Uppsala where they have thrived and been depicted. They have not previously been described. Linnaeus asks the Secretary at the Royal Swedish Academy of Sciences [Kungliga Svenska Vetenskapsakademien, Pehr Wilhelm Wargentin] to engrave and print drawings of the plants and send them to Linnaeus, who will write something about them [Linnaeus presumably meant to publish an article in the transactions of the Academy of Sciences, see Linnaeus to the Academy of Sciences, 28 October 1758{L2429}]. They are already described very shortly, in the Species plantarum, but without illustrations, which they deserve.
P.S. An attached note was forgotten in Linnaeus’s last letter [Linnaeus to the Academy of Sciences, 19 September 1758{L2408}].