Astonished by the lovely row of plants on the window sill, I reached for my camera. The trifoliate leaves were three inches across! Had I been mistaken all my life thinking shamrock was clover? Of course I went to Google and — if you’re wondering too, read more.
Ahh, Shamrocks are indeed clover. The lovely plants on the window sill are Oxalis, wood sorrell — often given as a gift on St. Patrick’s day.
wikipedia.org/wiki/Oxalis_acetosella
The common wood sorrel is sometimes referred to as a
shamrock and given as a gift on St. Patrick’s Day. This is due to its trifoliate clover-like leaf, and to early references to shamrock being eaten. Despite this, it is generally accepted that the plant described as shamrock is a species of
clover, usually white clover (
Trifolium repens).
wikipedia.org/wiki/Shamrock
A
shamrock is a young sprig of
clover, used as a symbol of Ireland.
Saint Patrick, Ireland’s patron saint, is said to have
used it as a metaphor for the Christian
Trinity.
[1] The name
shamrock comes from
Irish seamróg, which is the
diminutive of the Irish word for clover (
seamair) and means simply
“little clover” or
“young clover”.
[2]
Shamrock usually refers to either the species
Trifolium dubium (lesser clover, Irish:
seamair bhuí)
[3] or
Trifolium repens (white clover, Irish:
seamair bhán). However, other three-leaved plants—such as
Medicago lupulina,
Trifolium pratense, and
Oxalis acetosella—are sometimes called shamrocks or clovers. The shamrock was traditionally used for its
medicinal properties and was a popular
motif in
Victorian times.
But that’s not the end of the story! An article in USA Today 3/17/2015 reports on surveys on the question of which plant is the real shamrock.
http://www.usatoday.com/story/news/2015/03/17/what-is-a-shamrock/24895523/ 
Ahh, Shamrocks are indeed clover. The lovely plants on the window sill are Oxalis, wood sorrell — often given as a gift on St. Patrick’s day.
wikipedia.org/wiki/Oxalis_acetosella
The common wood sorrel is sometimes referred to as a shamrock and given as a gift on St. Patrick’s Day. This is due to its trifoliate clover-like leaf, and to early references to shamrock being eaten. Despite this, it is generally accepted that the plant described as shamrock is a species of clover, usually white clover (Trifolium repens).
wikipedia.org/wiki/Shamrock
A shamrock is a young sprig of clover, used as a symbol of Ireland. Saint Patrick, Ireland’s patron saint, is said to have used it as a metaphor for the Christian Trinity.[1] The nameshamrock comes from Irish seamróg, which is the diminutive of the Irish word for clover (seamair) and means simply “little clover” or “young clover”.[2]
Shamrock usually refers to either the species Trifolium dubium (lesser clover, Irish: seamair bhuí)[3] or Trifolium repens (white clover, Irish: seamair bhán). However, other three-leaved plants—such as Medicago lupulina, Trifolium pratense, and Oxalis acetosella—are sometimes called shamrocks or clovers. The shamrock was traditionally used for its medicinal properties and was a popular motif in Victorian times.
But that’s not the end of the story! An article in USA Today 3/17/2015 reports on surveys on the question of which plant is the real shamrock.
http://www.usatoday.com/story/news/2015/03/17/what-is-a-shamrock/24895523/ 
