Journal Number 90
March 2004

THE COLUMN

Singularibas oblongus / "aestivalis" burgundy
By Eric Scanlen

Andrea Bradon, DoC Hamilton, was on the case for conservation of critically endangered Linguella puberulla, bravo!  She had enrolled the assistance of John Smith-Dodsworth and the Column to show her known sites around the Webbs/Billy Goat Tracks loop in the Coromandel Range on 10 November.  For the record, the trio located 101 plants with about 15 in flower, many of them already spent.

The Column already had "boring old" L. puberula on film so he concentrated more on the abundance
of Singularibas oblongus and S. "aestivalis" thriving in the shady moss along Webbs Track.  The orchids were most conveniently growing up the bank, often at eye level so examining their inner papillae with the 20X lens was a pleasure compared with lying on a muddy forest floor, as is usual.

Let us divert for a moment or two, to bone up on the background of these two taxa.

Hooker's original Nematoceras oblonga [1, 2 p29] had "Lip . . blood-red purple with transparent edges" and no mention of "dentiform papillae" on the disc.

Eleven years later, in his Handbook, Hooker revised the same orchid to, Corysanthes oblonga [3 & 2 p66] stating "Lip . . deep blood-red; margin pale", and still nothing about disc papillae and no sign of them in Fitch's included drawing, J76:33.

TF Cheeseman [4] in 1925, under Corysanthes oblonga, included, "centre of the disc with minute dentiform papillae" or in English, tooth-like pimples.  So he had inadvertently switched taxa, hadn't he?

HB Matthews, in his 1928 manuscript, [J61:16] quite rightly stayed with Hooker's original, ignoring Cheeseman's switch by describing Corysanthes "aestivalis" where he wrote, "Labellum . . blood red . .
the wide fimbriate border of various colours, expanded, . . lamina for half way up the orifice, more or less papillose."  Notice that the labellum margin is not "transparent" as was Hooker's Nematoceras oblonga.

Moore and Edgar [5] stuck with Cheeseman's error and also described Matthews' Corysanthes "aestivalis" under the classification Corybas oblongus, by including, "Labellum . . with a wide circular mouth . . short, retrorse hair-like calli, numerous near mid-line on inner surface." Retrorse, meaning hooked over, tells the Column that the specimen(s) they had must have withered because those "hair-like calli" are always straight and deepest purple in live specimens of Singularibas "aestivalis". But the "hairs" are easily visible, with a 20X lens, by silhouetting them against the upright white column.  Magnified, they are actually tapering towards rounded tips and up to 0.2mm long as in the figure to the right drawn from a projected image of a sectioned flower from the Shenstone Block, Te Paki.

Now that you, dear reader, have a sound grasp of what is meant by S. oblonga and S. "aestivalis"
(as interpreted by the Column) let us return to the Webbs Track studies.

What the trio found could be described as absolutely chaotic! a complete mix of characters from both taxa. There were large round mouthed labella with a pearly transparent halo at the margin with regular fimbria and a long apiculus as in Catherine Beard's drawing, J59:21, a bed of papillae on the disk for some and none for others.

There were oval mouthed ones with irregular fimbria and no transparent halo yet with a prominent bed of papillae on the disk (and half way up the sides) for some and no papillae for others.   Oh yes, and there were some S. "aestivalis" s.s. which HBM [J61:16] would have been proud of, with regulation "expanded" labellum mouth, irregular fimbria to a margin of irregular purple and white (HBM's "border of various colours"?) and the essential bed of papillae.   Then there were the standard S. oblongus Hook. f. with oval opening and regular white fimbria on a transparent margin as well as a group of three S. "aestivalis" s.s. except for their burgundy leaves (Photo. right).  Only alba and double flowered specimens were lacking in the Webbs Track multitude as before.

The Column has previously noted Singularibas with some swapped characters but never to this extent. The apparent rampant hybridisation does nothing to boost one's confidence in there being two distinct species or exactly what the parent species are.  What do you think?

Side issue: have you noticed that Singularibas have lateral petals at the back? unlike Nematoceras which invariably have sepals curling back at the base and standing up at the back.  Molloybas cryptanthus also have tall petals at the back.

References
Hooker, JD Flora Novae Zelandiae Part 1 1853, p. 250.
St George, Ian, The Hookers on the NZ Orchids NZNOG Historic series 1989.
Hooker, JD Handbook of the NZ Flora 1864, p. 266
Cheeseman, TF, Manual of the NZ Flora 1925 p. 365
Moore, LB & Edgar, E, Flora of NZ, Vol. II, 1970, p. 117.