ae 
REVISION OF THE GENUS OYEDAEA. 
By 8. F. Biaxke. 
INTRODUCTION, 
In 1836 De Candolle! proposed the genus Oyedaea, named for 
the early Spanish navigator Alphonso Oyeda, and based on the two 
new species O, verbesinoides and O. buphthalmoides, the first of which 
was figured soon afterward in Delessert’s Icones. In 1848 Gardner ? 
published O. angustifolia from Brazil, and described under Viguiera 
two species which were later referred to Oyedaea by Bentham and 
Hooker. He also described? the genus Serpaea with two species, 
one of which, S. oblonga, wrongly referred to Viguiera by Bentham 
and Hooker, was placed in Aspilia by Baker in 1884, while the other, 
S. ovata, which must be considered the type of his genus, was 
referred with three new species to Oyedaea by Baker, under the 
subgeneric name Serpaea. In 1858 two new species were published 
from Colombia by Triana,‘ O. cuerviana (Triana 1520, specimen 
no. 4), and O. helianthoides (Triana 1520, specimen no. 5). The 
types of these species I have not been able to examine, but from 
description the former seems correctly referred to this genus. 0. 
helianthoides, however, with a pappus of numerous caducous awns, 
must belong to Perymeniwm or more probably to Steiractinia. It is 
said by Triana to be identical with Helianthus scaber of the Willdenow 
Herbarium. 
In the Genera Plantarum of Bentham and Hooker® the genus 
Oyedaea, distinguished from Zexzmenia solely by its neutral rays, 
was divided into the three sections, Wedelioides, Serpaea (Gardn.), 
and Verbesinoides, and the number of species was estimated at 22. 
Hoffman * in 1890 gave the number of species as 15. The present 
writer,7 when revising the genus Dimerostemma Cass. (Serpaea 
Gardn.) in 1917, estimated the number of species of Oyedaea at 
about 20, but subsequent study has reduced this to 13. 
1 Prodr. 5: 576. 1836. 
2 Lond. Journ. Bot. 7: 293, 398-399. 1848. 
3 Lond. Journ. Bot. 7: 296. 1848. 
4 Ann. Sci. Nat. IV. 9:39. 1858. 
5 Gen. Pl. 2: 374. 1873. 
6 In Engl. & Prantl, Pflanzenfam. 4°: 238. 1890. 
7 Contr. Gray Herb. n. ser. 52: 8. 1917. 1 
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