This is a cultivar (or perhaps that should be cultivars) originates from the United States of America. Two trees were planted at the Brinkerhoff mansion which was owned by George Madoc Brinkerhoff in 1869. It is at North 5th St and Keys Avenue (515 East Keys), Springfield, Illinois, United States of America. S.A. Brinkerhoff was a friend of Lincoln and active in Illinois politics. He was also a horticulturalist. In 1870 He imported Ginkgo trees from Japan. As of 2020 two are still living and thriving, which both tuned out to be males.
Tree one (Brinkerhoff) which grows close to the house is a distinct and huge tree with a tiered branching habit. It has a single trunk about 2.4m DBH (Diameter at Breast Height, the standard method of expressing the girth of a tree) There are between 2.4m and 3.6m between the tiers of branching. The branch angle is 90 degrees. Overall habit of the tree is a very broad pyramid.
Tree two (Brinkerhoff South) is located at the southwest corner of the property adjacent to 6th street. This tree has a single straight bole with the first limbs are more than 20 feet above ground. The tree has a narrower crown with multiple terminals in the upper third.
In 1990 Stan Tyson harvested some scion material from new growth coming from a pruning scar. (Specifically, a water sprout). One of these grafts is at Nauvoo Restoration, Inc, Nauvoo, Illinois, US.A. This tree has proven to be female. It has the same distinct branching habit as the male parent. Two seasons elapse before a new tier of branches will occur. This female is referred to as (Brinkerhoff 2).
The tree in the National Collection of Ginkgo biloba & Cultivars came from a scion taken from a tree in the Nauvoo collection (Brinkerhoff 2). Now, it is not uncommon for a Ginkgo in isolation to produce a shoot of the differing gender (this is one of the reasons why they have been able to survive), but it is unusual in cultivation.
Our thanks to Stan Tyson of Rivendell Botanic Garden, 10932 Prairie Creek Road, New Berlin, Illinois, 62670, U.S.A for this fascinating account of how (Brinkerhoff 2 came into being).