Family 2. OXALIDACEAE 



By John Kunkel Small 



Herbs, commonly with horizontal or bulb-like rootstocks, or shrubs or 

 trees. Leaves alternate, sometimes all basal, rarely reduced to phyllodia ; 

 stipules free, aduate to the petiole, or obsolete ; blades compound, commonly 

 palmately or pinnately 3-foliolate or often several-many-foliolate, or rarely 1- 

 foliolate, the leaflets various, but predominately with obcordate or obreniform 

 blades. Flowers perfect, nearly regular but unsymmetrical, borne in simple 

 or compound cymes which terminate peduncles. Calyx of 5 herbaceous, or 

 rarely petaloid, sepals. Corolla of 5 variously colored, or white, petals. 

 Androecium of twice as many stamens as there are sepals, in 2 rows ; filaments 

 united at the base, the longer ones sometimes appendaged on the back ; anthers 

 2-celled, versatile. Gynoecium 5-carpellary, the carpel-bodies united ; styles 

 distinct or merely coherent ; stigmas terminal or introrse, entire or cleft. 

 Ovules several or many in each carpel, or rarely only 1 or 2. Fruit a capsule 

 w T ith each carpel opening by a longitudinal valve, or a berry. Seeds trans- 

 versely wrinkled. 



Fruit a capsule ; herbs or diffuse shrubs. 



Valves of the capsule permanently adnate to the capsule-axis ; leaf-blades 1-3-foliolate. 



Plants acaulescent, with short or long rootstocks or sometimes with large roots which give 

 off short caudices. 

 Sepals without apical tubercles ; rootstocks elongate, merely scaly at the apex. 

 Cyme 1-fiowered, subtended by 1 or 2 clasping bracts ; capsules of 



the petaliferous flowers globose to ovoid. 1. Oxalis. 



Cyme several-flowered, subtended by a whorl of narrow bracts ; 

 capsules slender-fusiform or columnar. 

 Cyme umbel-like ; stigmas entire ; corolla funnel-form. 2. Hesperoxalis. 



Cyme dichotomous ; stigmas 2-lobed ; corolla salverform. 3. Otoxalis. 



Sepals with apical tubercles ; rootstocks bulb-like, solitary or several 

 together and connected. 

 Plants with elongate rootstocks which bear bulblets at the nodes. 4. Bolboxalis. 

 Plants with coated bulbs. 5. Ionoxalis. 



Plants caulescent. 



Leaf-blades 1-foliolate ; stipules free, bristle-like ; stigmas introrse. 6. Monoxalis. 

 Leaf-blades 3-foliolate ; stipules appearing as mere dilations at the 

 base of the petiole ; stigmas terminal. 

 Leaflets pinnate ; flower-stalk jointed ; capsule drooping ; stigmas 



2-cleft. 7. Lotoxalis 



Leaflets palmate ; flower-stalk not jointed ; capsule erect ; stigmas 

 capitate. 8. Xanthoxalis. 



Valves of the capsule radiately spreading ; leaf-blades many-foliolate. 9. Biophytum. 



Fruit a berry ; trees. 10. Averrhoa. 



1. OXALIS L- Sp. PI. 433. 1753. 



Oxys (Tourn.) Adans. Fam. 2 : 388. 1763. 



Acaulescent herbs with elongate scaly rootstocks. Leaves approximate or crowded 

 near the apex of therootstock or on a branch of it, with long petioles and palmatelv 3-foliolate 

 blades, the lateral leaflets somewhat inequilateral. Petaliferous flowers borne in a 1-flowered 

 cyme which is subtended by one or two clasping bracts. Cleistogamous flowers borne on 

 peduncles arising below those of the petaliferous flowers. Sepals 5, thick, the inner and 

 the outer ones nearly equal. Petals 5, broadened upward, mostly rounded at the apex. 

 Stamens 10, united at the base into a tube which is much shorter than the shorter filaments. 

 Ovary as thick as long, each carpel bearing one or two ovules ; styles much longer than 

 the ovary. Capsules of the petaliferous flowers globose to ovoid, larger than those of the 

 cleistogamous flowers, beakless. 



Type species, Oxalis Acetosella L. 

 Voi,ume 25, Part 1, 1907] 25 



