Oxalis tetraphylla Cav.

Global description
Oxalis tetraphylla is an herbaceous plant in clumps, reaching 30 cm tall, with fleshy root full of reserves, topped with a bulbous underground stem. The leaves are long-stalked, composed of four triangular leaflets with rounded or truncated end. Pink flowers, with greenish center, are grouped in small umbels carried by long stalks that exceed the leaves. The fruit is a cylindrical capsule with several loculus, containing ovoid pointed seeds of reddish color.
 
Growth habit
Tufted herb without aerial stem, reaching 30 cm tall, with long-stalked leaves with 4 leaflets and with long stalked pink inflorescences.
 
Underground System
The taproot is full of reserves. It is turnip shaped, may be branched and measure 3 to 4 cm in diameter. The stem is reduced to a disk carrying scales that form a globular or widely ovoid bulb, 4 cm long and 3 cm in diameter. The protective scales are scarious, brownish or reddish in color. The outer scales (14 to 18 mm long and 1-12 mm wide) are linear, ending with a sharp point, covered with 3 to 5 ribs. The inner scales (15 to 17 mm long and 5-8 mm wide) are largely sub triangular, abruptly narrowed to a point, covered with 7 to 14 ribs. The yellow colored feeding scales (3 to 7 cm long and 2 to 7 cm wide), are thick and rigid and covered with 3 to 7 ribs. Stipules (12 to 30 mm long and 4 to 13 mm wide) of white or red color, are thin, expanded at the base, open at the end, covered with 5 to 7 protruding ribs. Scales and stipules are ciliated on margin and has on the ribs, rigid red colored bristles of 5 to 6 mm long facing forward
 
 
Stem
The stem is without aerial part, limited to an underground disk overcoming the root.
 
Leaf
The leaves consist of four leaflets located at the end of a petiole of 5 to 30 cm long, smooth or slightly pubescent. The petiolules are very short, fleshy, pubescent. The 4 glabrous leaflets (2 to 7 cm long and 2.5 to 7.5 cm wide) are sub circular or sub-triangular, with obtuse triangular base, and rounded or truncated, rarely indented and sometimes mucronate apex. They are unequal in size, usually with a purple or black middle region or the whole lower third black or purple, with pubescence of simple hairs. In general, some translucent or dark spots are present in the upper part of the blade near the margin.
 
Inflorescence
The inflorescence is a pseudo-umbel, 3 to 12 flowers, gathered in bifid cymes, and carried by a peduncle, reaching up to 50 cm long. Bracts and bracteoles are small, hyaline.
 
Flower
The pedicel of flowers (up to 1.7 mm long) is articulated near the base. Sepals are oblong to elliptical, 7.5 to 4 mm long and 1 to 2 mm wide, glabrous or with variable pubescence, sometimes with 2 orange calluses near the end. The obovate petals, with a triangular base and rounded end, are 2 to 5 times longer than the sepals. They are purple to pink in color with a greenish-white base. The stamens are of 2 types: long (2.5 to 4 mm) with pubescent and glandular filament above a median ligule; short (1.5 to 2.5 mm), with glabrous, expanded filaments welded on 1/4 or ½ of the basal. The ovary with several loculus is surmounted by a usually elongated style.
 
Fruit
The fruit is a smooth cylindrical capsule, 13 mm long, ending in a sharp point. It consists of several loculus each containing 4-5 seeds. The calyx accompanies it and reaches ¼ of its length.
 
Seed
The seed is oval, pointed at the end, compressed. It has a rough surface of red color.