Alternanthera.] AMARANTACEAE, 413_ 
ALTERNANTHERA Forsk. !717%- 
Annual or perennial herbs, usually prostrate or decumbent, rarely erect, 
glabrous or more or less pubescent or tomentose. Leaves opposite. Flowers 
small, whitish, capitate; heads sessile in the axils of the leaves, often 
clustered. Perianth 5-partite ; segments unequal, the anterior and 2 pos- 
terior flattened, the 2 lateral innermost, concave. Stamens 2-5 ; filaments 
short, connate at the base into a membranous cup, with or without inter- 
vening staminodia ; anthers 1-celled. Ovary orbicular or obovoid ; style 
short or almost wanting ; stigma capitellate or rarely 2-fid ; ovule solitary, 
pendulous from an elongated basal funicle. Utricle compressed, ovoid or 
orbicular or obcordate ; margins often thickened or winged. Seed vertical, 
lenticular ; testa coriaceous. 
A small genus of 16 or 18 species, mainly tropical or subtropical, most abundant 
in America. The New Zealand species is a common weed in warm countries. 
l. A. denticulata Ak. Br. Prodr. (1810) 417.—A prostrate or decum- 
bent herb. Stems numerous from the root, branched, creeping and rooting, 
sometimes ascending at the tips, 4-18 in. long., glabrous or with 2 opposite 
pubescent lines. Leaves variable in size, 4-3 in. long, linear-lanceolate to 
. linear-oblong or oblong-obovate, obtuse or acute, narrowed to the base, 
entire or obscurely denticulate, glabrous or pubescent in the axils. Flowers 
ageregated in dense axillary clusters }-4in. diam., minute, whitish, about 
zzin. long. Perianth-segments glabrous, rigid, acute. Stamens 2-3. 
Utricle broadly obcordate, with broad corky wings.——A. Cunn. Precur. 
(1838) n. 367; Raoul Choix (1846) 43; Benth. Fl. Austral. v (1870) 249 ; 
Mog. DC. Prodr. xiii, 11 (1849) 356. A. sessilis R. Br. Prodr. (1810) 417 ; 
Hook. f. Fl. Nov. Zel. i (1853) 212; Handb. N.Z. Fl. (1864) 234; Cheesem. 
' Man, N.Z. Fl. (1906) 577. 
Nortu Istanp: Marshy places from the North Cape southwards to Rotorua and 
Hawke’s Bay. rare and local to the south of Auckland. Sea-level to 1000 ft. | 
This was referred by Hooker to the widely distributed A. sessilis R. Br.; but 
later writers usually place it under A. denticulata, which is an abundant Australian 
plant. 
Family XXXVI. NYCTAGINACEAE. 
Herbs or shrubs or trees. Leaves opposite or less frequently alternate, 
simple, entire, exstipulate. Flowers hermaphrodite or unisexual, often 
involucrate, usually arranged in cymose panicles. Perianth inferior, petaloid, 
monophyllous; tube persistent and enveloping the fruit; limb with 
3—5-plicate lobes. Stamens variable in number (1-30), usually 6-10, hypogy- 
nous ; filaments often unequal, inflexed in bud; anthers didymous. Ovary 
superior, 1-celled ; style simple, terminal ;. stigma small, entire or multifid ; 
ovule solitary, basilar, erect. Fruit a utricle with a membranous pericarp, 
firmly enclosed in the thickened or hardened base of the perianth-tube, 
which falls off with it. Seed erect, with a thin adherent testa; albumen 
farinaceous or fleshy ; embryo with foliaceous cotyledons usually wrapped 
round the albumen, radicle inferior. 
A small family, of no economical importance, with the exception of 2 or 3 wide- 
ranging genera almost wholly confined to tropical America. Genera 23; species about 
200. The single New Zealand genus is distributed over the shores of most tropical 
countries. ; 
