Gerbera Serrata

Characteristics of Gerbera Serrata:

Roots 1-(-4) mm wide. Leaves 6.5-20 cm long, 0.5-3.4 cm wide. Petiole 2-9.4 cm long, 0.5-1.5 cm wide, up to about 3 mm at the base. Lamina 3.5-13 cm long, varying from linear to lanceolate or more rarely narrowly oblong-elliptic; apex tapering, base cuneate or sometimes truncate, rarely narrowly and somewhat indistinctly cordate; margin subentire (or seemingly entire), subsinuate or sinuate with :t irregular, rather remote incissions, remotely crenate-toothed (in linear leaves rarely without teeth). Upper surface dark grass green or more dull, :t shiny, somewhat wrinkled, glabrous or very sparsely light or whitish pilose-villose; lower surface persistently greyish-yellow to yellowbrownish, rather softly and thinly, appressed, almost velvety tomentose, sometimes overlaid by a few villose
hairs; only the midvein on the lower surface prominent, brownish, glabrous to somewhat pilose-villose; margin glabrous or similarly hairy.

Scapes 1-3(-5), 10.5-45 cm long, 1-2.5 mm wide; bracts subulate, a few mm long, few to several; scape rather sparsely whitish pilose in the lower part, thinly yellow-brownish velvety felted-tomentose above. Involucral bracts 3-15 mm long, 0.5-3 mm wide, subseriate, lanceolate to narrow elliptic.

Photo to follow

Heads 10-20 mm long, 15-30 mm wide. Rays white or white tinged pinkish, lower surface often dark red to purple; tube 3.5-5 mm long, lower limb 10-20 mm long, 1-4 mm wide, upper limb 2-6 mm long, style 1.5-3.5 mm long. Disc florets with the tube 4-7 mm long, lobes 1.5-4 mm long.

Achenes not seen mature. Pappus whitish to whitish-tawny.

Distribution: Gerbera Serrata is found along the coast around Swellendam and eastwards to Humansdorp. (0?)-200-1250 m.

Ecology: On sandstone, slopes, fynbos, false fynbos, in open veld and loamy grasslands, on top of hills, and in burnt areas, sometimes frequent.

Flowering season: Aug.-Feb.

Gerbera Serrata is recognized by the narrow, usually lanceolate and sinuate, but sometimes linear and subentire leaves. The involucral bracts are more distinctly subseriate than in the other species.

This species has generally been named Gerbera ferruginea (Dc. 1838), probably mostly because of the importance of the Prodromus. The type of G. ferruginea has only dentate or subsinuate, relatively broad leaves, and De Candolle was himself aware that his species might be within the limits of the Thunberg species Arnica serrata, the type of which he never saw. He therefore only referred to A. serrata as a probable synonym (compare the discussion under G. Tomentosa).

While typical specimens of G. linnaei and G. ferruginea Dc. are easily separated, there is a small group of (often old) sheets which pose severe problems. Their collecting place is rarely indicated.

Firstly, a few specimens – all collected around Swellendam – have linear, almost entire, but remotely denticulate leaves. This form was given taxonomic rank by Harvey, who referred it to G. linnaei as a val. linearis (Harvey 1865). Dummer (1914) moved it under G. ferruginea.

Secondly, some specimens are intermediary in leaf form between G. linnaei and G. ferruginea Dc., having deeply sinuate leaves (1/3 to 1/2 of the leaf-width). Such specimens are identical with the taxon A. serrata Thunb. They are collected around Swellendam and eastwards to Riversdale. If G. ferruginea is included in A. serrata, the latter name must be used for the species. Actually both Harvey and Dummer quoted A. sermta Thunb. as a synonym of G. ferruginea Dc., but both authors nevertheless kept De Candolle’s name as the correct one. The combination Gerbera Serrata has only been used once, when it was proposed by Druce in a flora-list in 1917.

Both val. linearis and A. serrata are in all but leaf shape identical with G. ferruginea Dc. (only one doubtful collection exists: Stoke s.n. (Herb. No. 62092)(SAM); several collections are a mixture of G. linnaei and the forms discussed here). If these taxa were the results of hybridization between G. linnaei and G. ferruginea DC., one would expect the hybrids to be intermediary in several aspects, especially as regards the characteristic brownish tinged pappus of G. linnaei, which should be apparant in the hybrids. Besides, in the case of A. serrata, this form is reported as far eastwards as Riversdale, i.e. well separated from the easternmost known occurrence of G. linnaei. It therefore seems reasonably safe to conclude that G. ferruginea should be included in A. serrata.

In respect to var. linearis, only part of the type collection (and one or two other collections) actually match Harvey’s protologue description. All other sheets are more or less intermediary in leaf form between G. ferruginea and A. serrata. Var. linearis is thus nothing more than a form of G. serrata, without taxonomic rank. However, it is, admittedly, peculiar that the linearis form apparently only occurs around Swellendam, i.e. in the westernmost part of the Gerbera Serrata distribution area, where typical forms of G. ferruginea DC. are rare. Therefore the problem may not be finally settled.

It appears that G. linnaei merges into Gerbera Serrata through seemingly intermediary forms in the small sympatrie zone around Swellendam. Here we find all the taxa discussed, while the leaf form is typically ‘G. ferruginea’ in all areas east of Riversdale (sometimes approaching ‘A serrata’). Another possibility would therefore be to unite all these taxa within the limits of one single species. It is interesting to note that Harvey (1865) claimed that G. ferruginea DC. (incl. A. serrata Thunb.) might be merely an undivided form of G. linnaei!
It should be noted that some confusion may be added by the fact that G. linnaei has sometimes leaves only pinnatipartly dividedespecially when young. It is also possible that the brownish pappus colour may fade somewhat in old herbarium sheets. Both factorsseem to occur in the collection Ecklon & Zeyher 176 . . 90.9, which must be referred to G. linnaei.

Distribution of Gerbera Serrata (Thunb.) Druce.

Source: Opera Botanica 78 1985

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