Hi Georgina!
You’ll find the family at N:o 134 in Vårfru rote, Lunds domkyrkoförsamling AI:11 (1821–1825), page 49. I’ve done some research on this family in the past, and found out that Nils Fredrik’s father Magnus* Peter Landgren was born in Lund on 23 April 1779 (he died in Lund on 10 January 1834) to svarvaren (turner) Peter Landgren (born about 1745, died on 8 Sept. 1806 in Lund) and his wife Bengta Christina Jeppsdotter (born in Lund on 14 Aug. 1745, died in Lund on 30 Mar. 1811), and that his mother Botilla Hagman was born in Lund on 9 April 1778 to betjänten (valet? He later worked as a tailor) Johan Hagman and his wife Cecilia Andersdotter (they seem to have left Lund after 1787).
Magnus Landgren and Botilla Hagman hade eight children, born (and some of them died) in Lund:
Barn:
1. Johannes Landgren, born 10 Jun. 1803.
2. Lars Peter Landgren, born 4 Oct. 1805.
3. Christina Landgren, born 1 Mar. 1808, died 18 Dec 1808.
4. Nils Fredrik Landgren, born 10 Dec 1809.
5. Olof Landgren, born 30 Jun. 1812.
6. Magnus Landgren, born 28 Feb. 1815.
7. Christina Landgren, born 26 Jan 1818, died 15 Jun. 1819.
8. Alexander Landgren, born 4 Nov. 1821, died 26 Feb. 1823.