Herbs, annual or perennial, erect, prostrate or often cushion-forming. Leaves opposite, rarely somewhat whorled, exstipulate, oblong, oblong-elliptic, oblong-lanceolate, ovate, orbicular, elliptic, elliptic-lanceolate, linear, linear-lanceolate or linear-subulate. Flowers solitary, terminal or in dichasial terminal or axillary cymes, usually 5-merous. Sepals 4 or 5, free, herbaceous throughout or scarious-margined. Petals
entire or lacerate, white or pink, rarely absent. Stamens 2 - 10, on a hypogynous disc, those opposite to sepals glandular-thickened at base. Ovary 1-locular; styles 2 or 3 (-4), filiform. Capsules 2- 6-valved, short, rarely exceeding sepals; seeds few or many.
Temperate and arctic regions; ca 250 species, 24 species in India.
Notes.
Growing at various altitudes, at high altitudes sometimes forming very
dense, globose tufts of the size of a human head. In alpine regions smaller stunted forms
are found.
Literature.
WILLIAMS, F. N. (1898). A revision of the genus Arenaria. J. Linn. Soc., Bot. 33: 326 - 437.
KEY TO THE SPECIES
| 1a. Styles 2; capsules 4-valved (styles 2 - 3; capsules 4 - 6-valved in A. melandryiformis)
|
2
|
| b. Styles 3; capsules 6-valved
|
6
|
| b. Flowers in cymes (solitary in A. littledalel)
|
4
|
| b. Petals shorter than sepals or absent
|
5
|
| 6a. Leaves hardened and coriaceous or membranous along margins and apex
|
7
|
| b. Leaves herbaceous or with scarious margins, otherwise pungent and setaceous
|
12
|
| 7a. Leaves not densely imbricate, oblong-lanceolate, elliptic or ovate-elliptic, acute or acuminate; sepals
acute, usually hardened along margins and apex
|
8
|
| b. Leaves densely imbricate, linear to linear-subulate or lanceolate; sepals obtuse or subacute,
membranous along margins and apex
|
10
|
| b. Sepals ovate-elliptic
|
11
|
| 12a. Leaves mostly linear to subulate, markedly scarious- margined; sepals mostly variously
lanceolate
|
13
|
| b. Leaves mostly not linear to subulate, not markedly scarious-margined; sepals mostly variously ovate
|
19
|
| b. Petals shorter than sepals
|
15
|
| b. Sepals 3-nerved; anthers not black
|
17
|
| 19a. Leaves subulate, setaceous and pungent; sepals markedly hard at base, becoming ligneous in fruit
|
12.
Arenaria griffithii
|
| b. Leaves not subulate, herbaceous, sometimes coriaceous; sepals neither hard at base nor becoming lig-neous in fruit
|
20
|
| 20a. Perennials with
sterile leafy shoots along with flowering shoots
|
21
|
| b. Annuals without sterile leafy shoots
|
22
|
| 21a. Leaves linear to lanceolate, acute or obtuse at apex; seeds winged
|
3.
Arenaria compressa
|
| b. Leaves ovate to orbicular, rounded at apex; seeds not winged
|
23
|
| 23a. Sepal with a dorsal pubescent nerve; petals longer than sepals; seeds transversely striate
|
17.
Arenaria neelgherrensis
|
| b. Sepal without a dorsal pubescent nerve; petals shorter than sepals; seeds smooth
|
18.
Arenaria orbiculata
|
