Pauridia serrata (Thunb.) Snijman & Kocyan (2013: 29)

Snijman, Deirdre A., 2014, A taxonomic revision of the genus Pauridia (Hypoxidaceae) in southern Africa, Phytotaxa 182 (1), pp. 1-114 : 65-68

18. Pauridia serrata (Thunb.) Snijman & Kocyan (2013: 29) . Fig. 29

Bas.:— Fabricia serrata Thunberg (1779: 29) ≡ Hypoxis serrata (Thunb.) Linnaeus (1782: 197) ≡ Ianthe serrata (Thunb.) Salisbury (1866: 44) ≡ Spiloxene serrata (Thunb.) Garside (1936: 268) . Type (lectotype designated by Snijman & Kocyan 2013: 29):— SOUTH AFRICA. [Cape] Cap. b. Spei, Thunberg s.n. (UPS-THUNB! No. 8262 [image])

Plants (3.5–) 7–30 cm tall, sometimes clumped. Corm somewhat ovoid to globose, 8–19 mm diam., covered with pale brown fibrous tunics, rarely just distally, inner tunics often encrusted with white crystals, cormlets occasionally developing near base; fibres finely reticulate, detaching from basal disc, sometimes extended into a neck up to 13 mm long; roots spreading from near corm base or occasionally tangled around corm, epidermis often felt-like. Cataphylls membranous, up to 30 mm long. Leaves 3–9(–16), sheathing at base up to 70 mm, suberect to spreading, linear, sometimes sinuate, 60–220 × (0.5–)1–3(–4) mm, tapering evenly upwards, deeply to shallowly canaliculate, sometimes wiry, shiny to dark green, margin with widely spaced, minute, often recurved, multicellular teeth, sometimes hyaline proximally, occasionally entire. Inflorescences 2–5 in flower at a time, up to 15 when fruiting, 1-flowered, shorter or longer than leaves; scape 10–60(–80) × 0.7–1.0 mm, subterete, pale green; bracts 2, filiform, hardly clasping pedicel, 1.8–5.0(15.0) × 0.2 mm, pale greenish or colourless. Flower pedicellate, stellate, bright yellow, occasionally white or rarely orange, backed with green and outlined with red in outer whorl, sometimes with pale yellow or white between broad green central stripe and reddish rim, often narrowly striped with green in inner whorl, unscented; pedicel suberect, spreading in fruit, 40–120 × 0.6–1.0 mm, ca. terete, pale green to reddish brown; tepals 6, oblong-lanceolate, 7–16 mm long, outer 2.5–4.5 mm wide, minutely mucronate, inner 2.0– 3.5 mm wide. Stamens 6, suberect to spreading, straight to curved inwards, ca. equal, yellow; filaments inserted on ovary rim, (1.0–)2.0–3.0 mm long, shorter than anthers; anthers linear-oblong, latrorse, 4–10 × 0.7–1.0 mm, basal lobes up to ca. 0.2 mm; pollen yellow. Ovary subcylindrical to narrowly obconical, 4.0–12.0 × 1.2–2.0 mm, fully 3-locular or becoming 1-locular distally, often narrowed distally for up to 1.0 mm long; style 0.3–1.5 mm long, stigma branches erect to slightly spreading, narrowly lanceolate, 3–8 × 0.5–3.0 mm, slightly shorter to equalling stamens, yellow, with short basal lobes reaching down to style base, densely papillose. Capsule subcylindrical to narrowly obconical, often curved, 5.5–17.0 × 2–6 mm, dehiscence lengthwise close to septa. Seeds depressed ellipsoid, 0.7–1.0 × 0.5–0.8 mm; testa dark brown, of isodiametric cells, outer periclinal cell walls almost entirely hemispherical. Flowering period: (late May–)June–September(–rarely November at high elevations).

Distribution and habitat:— Pauridia serrata is widespread from northern Namaqualand southwards along the inland escarpment of Northern Cape through to the Cape Peninsula and Gordon’s Bay, Western Cape ( Figs. 30 & 31A ). The associated vegetation is shale shrubland in northern Namaqualand as well as various types of dolerite, shale, and granite renosterveld in the central and southern parts of the geographic range.

Diagnostic features:—With a particularly thick cuticle, the linear, canaliculate leaves of Pauridia serrata have a smooth and often wiry appearance when dry. As the epithet suggests, minute, widely spaced, recurved teeth are often present on the leaf margin. The diagnostic value of this feature, however, is diminished by its variability. P. serrata is most easily recognized by the solitary flowered inflorescence which has two filiform bracts that hardly clasp the base of the pedicel. In addition, the flower has subequal inner and outer stamens in which the filaments are characteristically much shorter than the anthers. Despite the inflorescence having been reduced to a single flower, P. serrata is nevertheless floriferous, with some individuals producing up to 15 or more inflorescences per season. When in fruit, the species is most easily recognized by its unusually large (0.7–1.0 × 0.5–0.8 mm), dark brown seeds covered by a densely colliculate testa. Elsewhere in the genus seeds larger than 0.7 mm are found only in the closely allied P. linearis and in two distantly related species— P. canaliculata , which has unique, J-shaped seeds, and P. alticola which has seeds densely covered with hair-like projections.

Unlike the closely allied Atlantic Coast endemic P. linearis , which has orange flowers with a contrasting, dark or pale central eye, P. serrata nearly always has concolorous flowers. In the vicinity of Darling, near the Modder River, however, rare individuals of P. serrata may have a pale centre and almost amber-yellow flowers, but these plants are distinguished from true P. linearis by suberect stamens at anthesis which are as long as or slightly longer than the style, unlike the outspread filaments in P. linearis that more than double the length of the short, stubby style.

Variation:— Pauridia serrata exhibits a wide range of variation over its geographic range, especially in corm covering and leaf width. Most commonly the corms are densely tunicated, with downwardly growing roots. The fibres are soft, closely reticulate and free from the basal disc, whereas distally they are short-tipped or extended into a distinct neck reaching up to 13 mm long. In populations on the Hantam Plateau in the vicinity of Calvinia and from the coastal forelands between Langebaan and Cape Town, however, the corms are mostly covered by tangled roots with a felt-like epidermis leaving only a few fibres evident distally. Nel (1914b) originally described the plants with root-entangled corms from near Calvinia as Ianthe dielsiana , but given the many intermediate specimens now known, this is treated here as conspecific with P. serrata .

Plants on the Roggeveld Escarpment, Northern Cape, are typically small, some only 30 mm tall, and they have slightly broader (up to 3 mm wide), recurved leaves, thus differing from the linear (1–2 mm wide), spreading leaves which are most common within the species. Other broad-leaved forms (up to 4 mm wide) are also known from the granite hills of the southwestern Cape from Vredenburg to near Mamre. Growing in seasonal vleis, these luxuriant plants are generally tall (up to 210 mm) and densely leafy, often with larger flowers than those from other parts of the distribution range.

Although leaf width appears to be constant in these local forms, this localized variation may also be induced by differences in available moisture. Thus under drought conditions the leaf margins appear to become in-rolled due to diminished pressure in the bulliform cells below the adaxial epidermis and in the large, thin-walled cells between the vascular strands.

Although typically bright yellow, rare orange-flowered plants occasionally occur in a few populations on the Bokkeveld Escarpment, north of Nieuwoudtville, whereas on the Farm Matjiesfontein, southeast of Nieuwoudtville and on the Bloukransberg, southwest of Calvinia, populations of yellow-, cream- and white-flowered plants are known. In the remaining patches of renosterveld on the Bokkeveld Plateau white-flowered plants are plentiful along the transition zone between Dwyka tillite and dolerite sills. The white-flowered populations of P. serrata , previously treated as var. albiflora by Nel (1914b) are recognized here as P. serrata subsp. albiflora , being morphologically and ecologically distinct from the yellow-flowered and widespread populations constituting subsp. serrata .

Key to subspecies

1. Flower yellow or rarely plain orange ................................................................................................................. subsp. serrata

- Flower white................................................................................................................................................... subsp. albiflora

Figures

FIGURE 29. Pauridia serrata subsp. serrata. A, whole plant; B, leaf in transverse section; C, scape apex, bracts and pedicel; D, stamen in dorsal view; E, style and stigma branches; F, ovary in transverse section; G, capsule; H, seed. Scale bar A = 20 mm; B = 1.2 mm; C–E, G = 4 mm; F = 2 mm. Scale bar H = 1 mm. Drawn by Tracey Nowell from Snijman 2380 (NBG!).

FIGURE 30. Distribution map for Pauridia serrata subsp. serrata from Northern and Western Cape, South Africa.

FIGURE 31. Distribution maps for A, Pauridia serrata subsp. albiflora from Northern Cape; B, P. linearis from Western Cape, South Africa.