Teacher and botanist Alexander Gilli was born in Penzing, Austria, where his father was a postman. He graduated from the University of Vienna in 1927 and became a science teacher. He specialised in natural history, maths and physics, but his favourite subject was botany.

Gilli's first botanical expedition took place in 1936, when he travelled to Iran. Afterwards he settled in Klagenfurt, Austria, and while teaching became involved with the Kärntner Landesmuseum (state museum of Carinthia), serving as custodian of the museum's botany department from 1940-1942.

Gilli married his wife, Gertraude, in 1940. Two years later he was called up to serve in the Second World War, initially being stationed at Husum on Germany's northern coast and then at the port of Gotenhafen. He also worked in Schleswig-Holstein for a period before returning to Vienna at the end of the war, resuming his school teaching and botanical work.

In 1949 Gilli was offered the opportunity to teach at the German School in Kabul, Afghanistan. Over the next two years he took the opportunity of making significant botanical collections in the country, covering areas from Jalalabad and Nuristan in the east through to the north-central regions of Bamyan and Samangan, and Farah and Herat in the west. His full itinerary in Afghanistan can be found in Feddes Repertorium volume 61 (1958).

Gilli's first child, Anita, was born in Afghanistan in 1950. The family returned to Vienna in 1952 and his second child, Wilfried, came into the world soon afterwards. Gilli continued teaching until his retirement in 1963, after which he was able to devote himself to botany, in particular floristics and systematics. During this period he took part in many congresses and published many papers. He was to be found nearly every day in the botany department of the Vienna Natural History Museum up until 1996, his sprightliness in old age noted by everyone who knew him. In his eighties he crossed Papua New Guinea, trekking from mission station to mission station and climbing a peak of more than 3,000 metres.

Publications by Gilli covered a wide geographical area, from the Vienna Woods to the Mediterranean, Macaronesia, Central Asia and tropical regions, especially Ecuador, East Africa, South Asia and Papua New Guinea. Above all, Gilli's main taxonomic interests were the genus Rubus and the Orobanchaceae (broomrape) family, but he described many new plants in other families and genera, too. His work on the plants and plant communities of Afghanistan was published in Feddes Repertorium in the series "Beiträge zur Flora Afghanistans" (1958, 1962, 1963, 1966) and in Vegetatio under the title "Afghanische Pflanzengesellschaften" (1969 and 1971).

Gilli lived to the grand age of 105 and at the time of his death was the oldest member of the Austrian Zoologisch-Botanischen Gesellschaft (the Botanical and Zoological Society), in which he had been very active. As well as his passion for botany he maintained an interest in chamber music throughout his life.

Sources:
M. Alam, 2009, "Plant Collectors in Afghanistan", Bulletin de la Société vaudoise des Sciences naturelles, 91(3): 324
A. Gilli, 1969, "Afghanische Pflanzengesellschaften", Vegetatio, 16(5/6): 307-375
W. Punz, 2008, Schriften Verein zur Verbreitung naturwissenschaftlicher Kenntnisse, 142: 97-106.