Portulaca L.

Annual or perennial, succulent, much branched herbs. Leaves dorsi-ventral or subterete, upper most clustered into foliar involucres with axillary hairs or scales. Flowers solitary or 2 - 30 in terminal capituli; receptacle infundibular with hairs or scales in the axils of bracts. Sepals 2, carinate or hooded, deciduous or persistent. Petals 4 - 6 (- 8), obovate, free or subconnate at base, macrescent. Stamens 8 - 9 in one whorl, inserted on calyx and adnate to petals. Ovary semi-inferior, 1-locular; styles 2 - 8 - armed, radiating. Capsules circumscissile at about middle. Seeds many, reniform, tubercled, rarely smooth.

Cosmopolitan, ca 100 species; 6 in India.

Literature. GEESINK, R. (1969). An account of the genus Portulaca in Indo-Australia and the Pacific. (Portulacaceae). Blumea 17: 275 - 307. LAL, J. & A.M. KHAN (1982). Pharmacognosy of the stems of Portulaca quadrifida L. and P.oleracea L. Proc.lnd. Acad. Sci. (Pl. Sci.) 91: 235 - 240. MATHEWS, J.F. & P.A. LEVINS (1986). The systematic significance of seed morphology in Portulaca (Portulacaceae) under scanning electron microscopy. Syst. Bot. 11: 302 - 308. NYANANYO, B.L. (1987). Taxonomic studies in the genus Portulaca L. (Portulacaceae). Feddes Repert. 98: 399 - 402. NYANANYO, B.L. & B.B. OKALI (1987). Cytological and morphological studies in Nigerian species of portulaca (Portulacaceae) in relation to their taxonomy. Feddes Repert. 98: 583 - 587. POELINITZ, K.V. (1934). Versuch einer Monographic der Gattung Portulaca L. Feddes Repert. 37: 240 - 329. SIVARAJAN, V.V. (1981). Taxonomic notes of the genus Portulaca Linn. in India. J. Bombay Nat. Hist. Soc. 78: 256 - 260.

Notes. The infrageneric treatments are attempted by Engelmann (1850), Poellnitz (1934), Geesink (1969), Mathews & Levins (1985) based on gross morphological characters taking into account species of particular geographical regions. Nyananyo (1987) considers them not satisfactory and recognizes two sections based on cytological, leaf morphological and anatomical, palynological, phytochemical and seed morphological evidences. The two sections are viz., sect. Portulaca (Engelmann) Nyananyo and sect. Rotundatae Poellnitz.

KEY TO THE SPECIES

1a. All leaves opposite; hairs or scales intra- and interpetiolar; membranous bracteoles absent

2

b. At least middle leaves cauline spirally arranged; hairs only axillaty, membranous bracteoles present

3

2a. Leaves visible; nodes with axillary hairs and no scales; flowers solitary

4. Portulaca quadrifida

b. Leaves mostly concealed by nodal appendages; flowers 2 - 7 in clusters

6. Portulaca wightiana

3a. Sepals distinctly carinate; axillary hairs not conspicuous, 0.5 - 1 mm long, deciduous

2. Portulaca oleracea

b. Sepals not carinate, at the most only apically keeled; axillary hairs prominent, more than 2 mm long, mostly persistent

4

4a. Flowers more than 2.5 cm across; petals 12 - 25 mm long; capsules ca 5 mm in diam.

1. Portulaca grandiflora

b. Flowers less than 1 cm across; petals ca 12 mm long; capsules 2 - 3 mm in diam.

5

5a. Plants erect or suffruticose; roots branched, woody; flowers pink

3. Portulaca pilosa

b. Plants spreading with tuberous main root; flowers yellow

5. Portulaca tuberosa

List of Lower Taxa