From his father's side Backer was a scion of a family of school teachers, from his mother's of the lesser peasantry. On his birth certificate his surname was written Bakker instead of Backer. Following time-honoured custom Backer, when fifteen, attended the State Teachers’ Seminary at Haarlem (1889–1893). His interest in botany had already expressed itself at the Seminary. After his finals he had posts at several small villages. This was the time that he came into contact with contemporary Dutch botanists including Hendrik Heukels (1854–1936) and Eduard Heimans (1861–1914).
Dutch East Indies (1901–1930)
Weltevreden
In 1901 Backer left the Netherlands and went to the Dutch East Indies. Between 1901 and 1905 he was employed as a primary school teacher at a private boarding school in Weltevreden (Batavia), (now Gambir, the centre of Jakarta in Java. Immediately he started to collect the plants around him, but to name them unreliable or incomplete treatises had been written, now also outdated and often not readily available. Thus, he decided to write one himself, with the flora of his immediate surroundings as a start, and this marked a milestone in his life and for Malesian botany.
Buitenzorg
He came into contact with Melchior Treub (1851–1910), the Director
of 's Lands Plantentuin in Buitenzorg (now the Bogor Botanical Gardens). Through Treub’s mediation Backer was given an appointment as Assistant at the Laboratory with as instruction to write a critical school flora for Java and to teach at the Agricultural School at Buitenzorg. From 1905 till 1924 Backer was employed at the botanical gardens. He scoured the fields and forests of Java, Madura, and the adjacent Kangean Islands, and so collected about 30,000 specimens while making daily trips of thirty to forty kilometres on foot.
Pasuruan
From 1924 till 1931 Backer was employed at the ‘Proefstation voor de Java-Suikerindustrie’ (Experimental Station for the sugar industry of Java) in Pasuruan on East Java. He wrote a flora on the weeds of the cane fields of Java (753 species).
The problem of volcano Krakatao
Melchior Treub sent Backer on two expeditions to the volcanoKrakatao, in 1906 and in 1908.[6][7] In 1929 Backer published his contentious book The problem of Krakatao, as seen by a botanist, in which he maintained that not all plant life had been destroyed by the gigantic eruption of the volcano, but that rootstocks and diaspores might have been buried to sprout again.[8][9][10][11] Indeed, this possibility cannot be ruled out completely because of the failure of the Government to undertake any research immediately after the 1883 eruption of Krakatoa. Only as late as June 1886 the first biologist, Melchior Treub, came to take stock, but grasses had already been observed on the slopes in 1884 by the Dutch geologistRogier Verbeek (1845–1926).[12][13][14][15][16][17]
Back in the Netherlands (1931–1963)
In 1931 Backer and his family returned to the Netherlands.[18] They first lived in Haarlem and then settled in Heemstede where he worked until his last years on his ‘magnum opus’, the Flora of Java.[19] Backer made Reinier Cornelis Bakhuizen van den Brink Jr. (1911–1987) co-author of the Flora of Java. On 22 February 1963 Cornelis Andries Backer passed away. The Flora of Java was posthumously published in three parts (1964–1968). In this flora about 6,100 species of flowering plants were described.
1908: Voorlooper eener schoolflora voor Java, Batavia, Departement van Landbouw, G. Kolff.
1909: De flora van het eiland Krakatau. In: De opneming van de Krakatau-Groep in Mei 1908. Jaarverslag van den Topographischen dienst in Nederlandsch-Indie over 1908. 4:189–191.
1911: Schoolflora voor Java (medeauteur: Dirk Fok van Slooten), Weltevreden, Visser & Co.
1912: Aanteekenboekje voor het plantkundig onderwijs in de lagere klassen van middelbare scholen (medeauteur: A.J. Koens), Weltevreden, Visser & Co.
1912: Sawah planten, De Tropische Natuur 1: 129–135.
1913: Kritiek op de Exkursionsflora von Java (bearbetet von Dr. S.H. Koorders), Weltevreden, Visser & Co.
1929: The problem of Krakatao as seen by a botanist, Weltevreden, Visser & Co., ’s-Gravenhage, Martinus Nijhoff.
1931: De vermeende sterilisatie van Krakatau in 1883, Vakblad voor Biologen XII: 157–162.
1936: Verklarend woordenboek der wetenschappelijke namen van de in Nederland en Nederlandsch Indië in het wild groeiende en in tuinen en parken gekweekte varens en hoogere planten, Groningen, P. Noordhoff N.V., Batavia, Noordhoff-Kolff.
1936: Verwideringscentra op Java van uitheemsche planten, De Tropische Natuur 25: 51–60.
2000: Reprint. Verklarend woordenboek der wetenschappelijke namen van de in Nederland en Nederlandsch Indië in het wild groeiende en in tuinen en parken gekweekte varens en hoogere planten, Amsterdam/Antwerpen, L.J. Veen.
^Backer, C.A. 1909. De flora van het eiland Krakatau. In: De opneming van de Krakatau-Groep in Mei 1908. Jaarverslag van den Topographischen dienst in Nederlandsch-Indie over 1908. 4: 189–191.
^Ernst, A. 1907. Die neue Flora der Vulkaninsel Krakatau. Vierteljahrschrift d. Naturf. Ges. in Zürich. Jahrg. 52: 289–363.
^Backer, C.A. 1929. The problem of Krakatao as seen by a botanist. Weltevreden, Visser & Co., ’s-Gravenhage, Martinus Nijhoff.
^Backer, C.A. 1931. De vermeende sterilisatie van Krakatau in 1883. Vakblad voor Biologen XII: 157–162.
^Winchester, S. 2003. Krakatoa: The Day the World Exploded: August 27, 1883. Harper Collins, New York, pages 209–316.
^Martí J. & Ernst G. 2005. Volcanoes and the Environment. Nature, 256–259.
^Treub, M. 1888. Notice sur la nouvelle flore de Krakatau. Annales du Jardin Botanique de Buitenzorg. 7: 213–223.