Oxalis stricta
 
Yellow Wood-Sorrel

Pistil

Regina
07-July-2017

The pistil is composed of five united carpels.  Note the pubescent styles.

I am including S. europaea within a larger S. stricta.  The key to the families in Budd's Flora requires "stamens usually separate or partly so, not in a column".  This is not true.  The filaments in S. stricta are united in a column around the pistil.  I have deleted that item from the family key answers below.

bullet

Stricta: Answers to key questions in Budd's Flora leading to this species. 
bullet

stem NOT rooting at nodes; NOT [stem often rooting at nodes]

bullet

stem erect or decumbent in age; NOT [stem creeping]

 

bullet

Oxalidaceae: Answers to key questions in Budd's Flora leading to this family. 
bullet

herbs; NOT [shrubs or trees]

bullet

plants terrestrial or semiaquatic; NOT [plants aquatic; leaves submerged or floating]

bullet

plants NOT with colored milky juice

bullet

plants with more than one normal leaf

bullet

some or all leaves alternate; NOT [leaves opposite, whorled or basal]

bullet

leaves with stipules; NOT [leaves without stipules, or having glands]

bullet

leaves of 3 leaflets; NOT [leaves palmately divided]

bullet

flowers with two floral rings

bullet

flowers regular in shape; NOT [flowers irregular in shape]

bullet

calyx regular; NOT [calyx irregular, some sepals smaller than others]

bullet

each petal distinct from the others

bullet

stamens 5 or 10; NOT [stamens usually numerous]

bullet

ovary of 5 united carpels; NOT [ovary of one or more carpels, either separate or enclosed by a fleshy receptacle]

bullet

fruit not beaked; NOT [fruit with a long beak]