Catasetum × fergusonii Dodson ex W.E.Higgins & Dalstr

Krahl, Dayse Raiane Passos, Schmal, Philippe, Chiron, Guy, Silva, João Batista Fernandes Da, Krahl, Amauri Herbert & Cantuária, Patrick De Castro, 2023, Catasetum × grasineideae (Orchidaceae: Catasetinae), a new nothospecies from Brazilian Amazon and taxonomic notes for the genus, Phytotaxa 594 (2), pp. 89-104 : 98

3. Catasetum × fergusonii Dodson ex W.E.Higgins & Dalstr ̂m (in Higgins & Dalstr̂m 2007: 103) (pro. sp.), nothosp. nov.

( Figure 6D ).

Type:— PERU. Arequipa: 10 kilometers West of Arequipa, ca. 1100 m [sie 2000 m], january 1976, G. Ferguson s/n (holotype: SEL, OIC-6748) .

Taxonomic Note: —The true taxonomic identity of this taxon was revealed through artificial crossings and germination in vitro carried out by J. Fernández G. It is a natural hybrid between C. saccatum Lindley (1840a: 76) and C. tenebrosum Kraenzlin (1910: 229) . The result of the artificial crossing has the same characters as those presented in the original description, differing only by the lip color (more yellow) which is clearly acceptable in hybrids since their morphology may present a large variability, included coloration. In addition, C. saccatum as well as C. tenebrosum show various morphological variations linked to the particular locality where they grow in Amazon, which may in any event lead to hybrid with large variations.

It is interesting to note that Higgins & Dalstr̂m (2007), when describing the taxon as an independent species, ignore the possibility of hybridization but use for comparison C. saccatum and C. tenebrosum as closest and more related species even though they show different features as for the arrangement of antennae (respectively, section Catasetum —asymmetric and crossed antennas / section Isoceras subsection Convergentes— symmetrical antennae that come towards each other). Another curious fact is the record made by M. Whitten, deposited in herbarium FLAS, mentioning that we are unaware of the possibility for this taxon to be a hybrid between C. saccatum and C. tenebrosum .

We can observe in C. × fergusonii that the lip is trilobed and saccate as in C. saccatum , whereas it is more or less triangular, as in C. tenebrosum . Its margin is sparsely lacerate/fimbriate what is an intermediate form, since the margin is dentate in C. tenebrosum and fimbriate/laciniate in C. saccatum . Besides the margin is reflexed as in C. saccatum . Finally, C. × fergusonii shows on the lip a callus which looks like a variation of the callus of C. tenebrosum (see Higgins & Dalstr̂m 2007).

Additional specimens examined:— PERU. Arequipa: road to Quilca. Cultivated, from Oak Hill Gardens; accessioned as Whitehill 0008, 04 october 1993, M. Whitten 93112 (FLAS-178428, photograph!) .

Figures

FIGURE 6. Hybrid Catasetum. A–B. C. × aripuanense. C. C. × dalastranum. D. C. × fergusonii. E–F. C. × mojuense. G–H. C. × yarigii. Photos A–B, D and G–H by J. Fernández G., C by F. Godoy and E–F by E. Pontes.