A shamrock is a young sprig, used as a symbol of Ireland. Saint Patrick, Ireland's patron saint, is said to have used it as a metaphor for the Christian Holy Trinity. The name shamrock comes from Irish seamrg [amo], which is the diminutive of the Irish word seamair g and simply means 'young clover'. At most times, Shamrock refers to either the species Trifolium dubium (lesser clover, Irish: seamair bhu) or Trifolium repens (white clover, Irish: seamair bhn). However, other three-leaved plantssuch as Medicago lupulina, Trifolium pratense, and Oxalis acetosellaare sometimes called shamrocks. The shamrock was traditionally used for its medicinal properties and was a popular motif in Victorian times. Botanical species There is still not a consensus over the precise botanical species of clover that is the 'true' shamrock. John Gerard in his herbal of 1597 defined the shamrock as Trifolium pratense or Trifolium pratense flore albo, meaning red or white clover. He described the plant in English as 'Three leaved grasse' or 'Medow Trefoile', 'which are called in Irish Shamrockes'. The Irish botanist Caleb Threlkeld, writing in 1726 in his work entitled Synopsis Stirpium Hibernicarum or A Treatise on Native Irish Plants followed Gerard in identifying the shamrock as Trifolium pratense, calling it White Field Clover. The botanist Carl von Linn in his 1737 work Flora Lapponica identifies the shamrock as Trifolium pratense, mentioning it by name as Chambroch, with the following curious remark: 'Hiberni suo Chambroch, quod est Trifolium pratense purpureum, aluntur, celeres & promtissimi roburis' (The Irish call it shamrock, which is purple field clover, and which they eat to make them speedy and of nimble strength). Linnaeus based his information that the Irish ate shamrock on the comments of English Elizabethan authors such as Edmund Spenser who remarked that the shamrock used to be eaten by the Irish, especially in times of hardship and famine.