Published in Bot. Repos. 1: 17 in 1798.
PlantList shows the name as unresolved but other texts show it as the basionym of Leucospermum formosum (Andrews) Sweet.
From Bot. Repos.:
Of all the varied genera of plants which decorate that mine of botanical riches, the Cape of Good Hope, and the adjacent country, no one stands more conspicuous than Protea.... It has been introduced to the Royal Gardens at Kew by Mr. F. Masson... Our drawing was made from a plant which flowered in the nursery of Messrs. Lee and Kennedy, in the year 1796, about the month of August.