Question: Ulmus × diversifolia, also known as the Diverse Leaved Elm, he recorded its distribution in which county town of Hertfordshire, England, and is also a civil parish in the East Hertfordshire district of the county?

Context paragraphs:
Ulmus × hollandica 'Wredei': The hybrid elm cultivar Ulmus × hollandica 'Wredei', also known as Ulmus × hollandica 'Dampieri Aurea' and sometimes marketed as Golden Elm, originated as a sport of the cultivar 'Dampieri' at the Alt-Geltow Arboretum, near Potsdam, Germany, in 1875.

Ulmus × diversifolia: Ulmus × diversifolia, also known as the Diverse Leaved Elm, was originally described by Melville in 1939 as a new species, "U. diversifolia", though he later believed it a natural hybrid of Coritanian elm, Plot elm and Wych elm.  He recorded its distribution in Hertfordshire, between Hatfield, Hertford and Watton-at-Stone, and in Suffolk, where it was common along the coastal plain from Ipswich and Felixstowe to Lowestoft and Beccles, occurring inland as far as Diss and Debenham, and probably extending further north into Norfolk and south towards Colchester, Essex.  He accordingly referred to it as "the East Anglian elm".

Gilston: Gilston is a village in the East Hertfordshire district of Hertfordshire, England.  It is located a little over one mile north of the town of Harlow in the neighbouring county of Essex.  Together with the nearby hamlet of Eastwick, it forms the civil parish of Eastwick and Gilston.  At the 2001 Census, the population was 180, at the 2011 Census reverting to the civil parish of Gilston and recording a population of 228.

Nasty, Hertfordshire: Nasty is a hamlet in the East Hertfordshire district of Hertfordshire, England.  It is in Great Munden civil parish, around 6 miles (10 km) north of Ware and around 7.5 miles (12 km) east of Stevenage.  At the 2011 census the population was included in the civil parish of Albury.

East Hertfordshire District Council: East Hertfordshire District Council is the local authority for the East Hertfordshire non-metropolitan district of England, the United Kingdom.  East Hertfordshire covers most of the eastern third of Hertfordshire, in the East of England region.  The Council itself is based in Bishop's Stortford, the largest settlement in the district, with a secondary council office in Hertford, the county town.

Anstey, Hertfordshire: Anstey is a village and civil parish in the East Hertfordshire district of Hertfordshire, England, about fifteen miles north-east of Stevenage.  According to the 2001 census the population of the parish was 338, reducing to 299 at the 2011 Census.  There are at least two books on the history of this village; the first is entitled "Anstey, a Hertfordshire Parish" written in 1929 by Rev Frank Ricardo Williams, M.A.  He was the rector from 1907–28,( died 19 May 1937).  The second is entitled "ANSTEY: Our True Surname Origin and Shared Medieval Ancestry" by G.M. Anstey and T.J. Anstey in which it is shown that all bearers of the surname 'Anstey' worldwide can trace their surname origin to Anstey in Hertfordshire.

Hertford: Hertford (/ˈhɑːfəd/, /ˈhɑːtfəd/) is the county town of Hertfordshire, England, and is also a civil parish in the East Hertfordshire district of the county.  Forming a civil parish, the 2011 census put the population of Hertford at about 26,000.

Ware, Hertfordshire: Ware is a town of around 18,800 people in Hertfordshire, England close to the county town of Hertford.  It is also a civil parish in East Hertfordshire district.  The Prime Meridian passes to the east of Ware.

Wareside: Wareside is a small village and civil parish in the East Hertfordshire District, in the county of Hertfordshire.  The population of the civil parish as of the 2011 census is 735.  It is approximately 3 miles away from the town of Ware (from where it probably took its name) and the larger town of Hertford, the county town of Hertfordshire.  Nearby villages include Widford, Hunsdon, Babbs Green and Bakers End.  Nearby hamlets include Cold Christmas and Helham Green.  The B1004 linking Ware to Bishop's Stortford goes through the village and the main A10 road can be picked up at Thundridge.  Fanhams Hall Road also links Wareside back to Ware.  Ware railway station on the Hertford East Branch Line is located two and a half miles away.

Ulmus × hollandica: Ulmus × hollandica , often known simply as Dutch elm, is a natural hybrid between Wych elm "Ulmus glabra" and field elm "Ulmus minor" which commonly occurs across Europe wherever the ranges of the parent species overlap.  In England, according to the field-studies of R. H. Richens, "The largest area [of hybridization] is a band extending across Essex from the Hertfordshire border to southern Suffolk.  The next largest is in northern Bedfordshire and adjoining parts of Northamptonshire.  Comparable zones occur in Picardy and Cotentin in northern France".

Supporting paragraphs: Ulmus × diversifolia Hertford
Answer: Hertford