Cressa
Accepted name/Authority/Place of publication:
CRESSA L., Sp. Pl. : 223 (1753)
Tribe:
Cresseae
Type Species:
Cressa cretica L., Sp. Pl. 1: 223. 1753, lectotype designated by Verdcourt, Fl. Trop. E Africa, Convolvulaceae 33 (1963).
Habit:
Rhizomatous cryptophytes, roots horizontal, geminate, with lateral branches leading upwards to produce above-ground parts. Perennial subshrubs or herbs, usually much-branched. Stems at first erect and them becoming decumbent, apparently short-lived, grey appressed pilose to sericeous.
Leaves:
Leaves on main branches often larger than those on the branchlets, the blade 1-12 mm long, lanceolate, ovate or elliptic to scale-like, sessile or shortly petiolate.
Inflorescences:
Inflorescences of solitary flowers, axillary, 5-8 mm long, sessile or on short peduncles, bracteates, in spicate to head-like clusters at tips of branchlets, bracetoles unequal in length.
Flowers:
Flowers small, no obvious fragrance; sepals ovate to obovate, imbricate; corolla salverform, the limb 5-lobed, the lobes mostly ovate, imbricate, spreading to reflexed; stamens exserted, the filaments filiform, the styles exserted; ovary 2-locular, 4-ovulate, styles 2, distinct to the base, the stigmas capitate.
Pollen:
3-colpate, cf. http://ag.arizona.edu/herbarium/assoc/projects/convolv/Cressa_australis.htm
Fruits:
Fruits capsular, ovoid, unilocular, 2-4-valved, usually 1-seeded.
Chromosome details
Origin:
Cressa cretica
Chromosome number:
28
Publication(chromosome):
Goldblatt, P. Index to Plant Chromosome Numbers, 1979-1981. Monogr. Syst. Bot. Missouri Bot. Gard. 8: 1–427 (1984).
Distribution:
Tropical and southern temperate regions. map
Ecology:
Halophytes, particularly irrigated fields, salt pans, coastal marshes. Apparently adapted for living in virtually any type of substrate from alkaline soils to volcanic lava or clays and sands.
Common names and uses:
alkali-weed (United States), panittanki (panit = dew, tanki = resting place; Tamil, India, Sri Lanka)
Number of Species:
4
Other information:
Flowers are diurnal.
Contributors: