Portulaca tuberosa Roxburgh (1832: 464)

Dalavi, Jagdish Vishnu, Tamboli, Asif, Pujar, Ramesh, Saliyavar, Basavaraj & Yadav, Shrirang, 2024, Reinstatement of Portulaca badamica from P. tuberosa with critical notes on variation in P. tuberosa, Phytotaxa 671 (3), pp. 293-300 : 297-299

Portulaca tuberosa Roxburgh (1832: 464) ( Fig. 2L–X and Fig. 3 ).

Lectotype (designated by Singh & Arigela 2022: 135, Figure 6): —[Icon] Portulaca tuberosa in Roxburgh (132: no. 2496).

Description:— Perennial, tuberous, succulent herbs. Roots tuberous, tubers 2–15 × 1–4 cm, conical to napiform, pale orange to dark brown in colour. Stem 5–40 × 0.3–1.0 cm in length, highly branched or arising tuft of the stem from apex of tuber, diffused, succulent, glabrous throughout, sparsely hairy at leaf axils. Leaves 0.5–4.0 × 0.2–0.6 cm, simple, linear, terete, fleshy, 2–4 at nodal portion to form whorl , reflexed at apex, sessile to subsessile, dark green. Flowers 1.5–3.0 cm across, white, pink, yellow, magenta, orange to dark red in color, sessile; sepals 2, ovate 0.2–0.7 × 0.1–0.4 cm, translucent, pale green; petals 4–6, 0.5–1.5 × 0.2–0.6 cm, obovate, acuminate at apex, white, cream, yellow, orange, magenta, pink to dark red coloured, connate at base; stamens 8–20, 2–5 mm in length, filaments connate at the base forming ring around the gynoecium; gynoecium 2–5 mm in length, ovary 0.10–0.25 × 0.1–0.2 cm, 2–5 carpellate, style 0.5–4.0 mm, erect, glabrous; stigma 0.5-2.5 mm, 4-12 fid, papillate. Fruit 3–5 × 1–4 mm, sub-globose to oblong, circum dehiscing capsule, operculum much longer than basal disc; seeds 30–60 per capsule, 0.30–0.65 mm, orbicular, testa almost smooth, black polished, with faint stellulate ornamentation.

Habitat:— The plant grows in sandy and gravelly to rocky areas characterized by a low humidity.

Distribution:— Christmas Islands, India, Jawa, Laccadive Islands, Lesser Sunda Islands, Maldives, New Guinea, Pakistan, Queensland, Sri Lanka, Western Australia ( POWO 2024). In India the species occurs in Andhra Pradesh, Bihar, Karnataka, Kerala, Lakshadweep islands, Maharashtra, Odisha, Pondicherry, Punjab, Rajasthan, Tamil Nadu, Telangana, Uttar Pradesh, West Bengal.

Notes:— Portulaca tuberosa is polymorphic species in India it shows six phenotypic forms namely form 1 (white form with > 2 cm long reflexed leaves) ( Fig. 3A–B ), form 2 (white with <2 cm short and non-reflexed leaves) ( Fig. 3C–F ), form 3 (yellow form) ( Fig. 3G ), form 4 (magenta form) ( Fig 3D ), form 5 (pink form) ( Fig. 3E ), and form 6 ( Fig. 3H–I ) all forms except form 1 shows close morphology and almost many of them are growing sympatrically detailed morphological attributes of each form are depicted in table. 2. However, seed micromorphology of all these forms is similar and all above-mentioned variations might be due to natural hybridization. Single individuals produce only particular type of flowers, there is no observation on individual having different colored flowers.

Molecular studies:— Recently Tamboli et al. (2022) studied the phylogenetic positions and biogeographic history of Indian endemic Portulaca species namely; Portulaca badamica , P. lakshminarasimhaniana and P. oleracea var. linearifolia . Their phylogeny revealed that P. badamica grouped with African Portulaca species viz P. massaica Phillips (2000: 689) and P. foliosa Ker Gawler (1824: 793) . Accessions of P. tuberosa included by Tabmoli et al. (2022) were grouped with another accession of P. tuberosa included by Ocampo and Columbus (2012). These phylogenetic evidence suggests that not only morphologically but also according to molecular studies both P. badamica and P. tuberosa cannot be placed together. Meanwhile, Sing and Arigela (2022) found P. badamica is conspecific with P. tuberosa based on superficial circumscription. To prove the distinctiveness of both species, we added additional sampling of P. badamica (JVD-1250) and P. tuberosa (JVD-1681A) to confirm their phylogenetic placements. Our reconstructed 50% Majority rule Bayesian phylogeny presented in figure 4 revealed that both the P. badamica accessions JVD-1250 and JVD-1261 grouped together (ML BS = 100% and BI PP value ≥ 0.90) and showed sister relationship with African taxa P. massaica and P. foliosa with ML BS = 66 % and BI PP value ≥ 0.50 ( Fig. 4 ). Both the specimens from different forms of P. tuberosa (JVD-1681 and JVD-1681A) grouped with sample by Ocampo and Columbus (2012) which is P. tuberosa (Acc. No. - OCAMPO & al. 1737) with ML BS = 99 % and BI PP value ≥ 0.90 ( Fig. 4 ). These phylogenetic results confirm that both the species phylogenetically placed in Pilosa clade ( Fig. 4 ) but in different groups P. badamica cannot be kept in anyway into P. tuberosa group.

Additional Specimens examined for Portulaca tuberosa :— INDIA. Andhra Pradesh: Pudimadaka , 28 September 1969, Rao 7209 ( BSID!) ; Krishna district, Bandar Fort RF, 22August 1984, P. Venkanna 5358 ( MH!) ; Goa: Rocky creek , near sea, Nagoa, 20 September 1964, S. Rao Rolla 102674 ( BSI!) ; Gujarat: Jakhav 18 September 1968, R. S. Raghavan, 114945 ( BSI!) ; Kerala: Muthakoda, 05 May , 1958, G. S. Puri 36370 ( BSI!) ; Odish: Gopalpur South , 7 October 1970, L. K. Banarjee 8340 ( BSID!) ; Puri Coast , 03 October 1972 G. N. Tri & R. N. R. 341 ( BSID!) ; Bhubaneshwar , 26 July 1973, H. Saxena 1058 ( JCB!) ; Rajasthan: Jodhpur-Bhimbharak , 31 July 1958, S. K. Jain 40222 ( BSI!) ; Tamil Nadu: Kancheepuram district , Walajabad, September 1826, R. Wight 6844 C ( CAL!) ; Chingleput (Chengalpattu) district , January 1884, s.c. s.n. ( MH00162102 !) ; Chingleput district , 28 October 1914, s.c. ( MH00162101 !) ; North Arcot district, Tippukadu RF, 165 m, 28 June 1963, K. Ramamurthy 16604 ( MH!) ; Ramanathapuram district, Mandapam , 29 September 1987, V. Balasubramaniam 1386 ( MH!) ; Rameswaram , 24 September 1944, D. Daniel s.n. ( MH00162110 !) ; South Arcot, Cuddalore , 30 August 1899, C. A. Barber 746 ( MH!) ; Telangana: Ramanagutta , 08 July 1996, R. Rajan 107981 ( BSID!) .

Figures

FIGURE 2. A–K. Portulaca badamica A.–E. Different stages of habit; F. Flowering twig; G. Flower; H. Stigma; I. Cleistogamous flower; J. Seeds; K. SEM of seed; L.–X. Portulaca tuberosa; L.–O. Different stages in different forms of P. tuberosa with distinct root tuber. P.–S. Flowers of white, orange, yellow, and pink forms; T.–V. Variation in stigmatic lobes; W. Seeds; X. SEM of seed (photos by J. Dalavi).

FIGURE 3. A–I. Different forms of Portulaca tuberosa (photos by J. Dalavi).

FIGURE 4. 50% majority-rule consensus Bayesian phylogenetic tree based on combined (ITS + ndhA + ndhF + trnT-psbD) data.Bayesian posterior probability values (represented with blue, green and red colour) and maximum likelihood bootstrap values (BPP/ML BS) are provided above branches.Asterisk (*) indicates ML BS values <50%. The herbarium number of each taxon is in the bracket after the taxa name. Phylogenetic positons of Portulaca badamica and P. tuberosa are highlighted in red colour.