Theodor Hartig [SEP] father
abbreviation is Hartig. He described many gall wasp species.
In 1842, Theodor Hartig described what is now known as the Hartig net, a network of fungal hyphae that penetrate feeder roots and surround epidermal cells. The Hartig net is part of the structure of ectomycorrizae, mutualistic symbioses between fungi and plant roots. 
He died in Braunschweig.
Works.
- 1836. Forstliches und forstnaturwissenschaftliches Conversations-Lexicon. Georg Ludwig Hartig and Theodor Hartig
- 1840. Über die Familie der Gallwespen. Zeitschrift für die Entomologie
Theodor Hartig
Theodor Hartig (21 February 1805 – 26 March 1880) was a German forestry biologist and botanist.
Biography.
Hartig was born in Dillenburg. He was educated in Berlin (1824–1827), and was successively lecturer and professor of forestry at the University of Berlin (1831–1838) and at the Carolinum, Braunschweig.
Hartig was the first to discover and name the sieve tube element cells (as "Siebfasern" - sieve fibres and "Siebröhren" - sieve tubes) in 1837. His zoologist author