Botanist Chaia Clara Heyn was born on June 13, 1924, in Cluj (Transylvania), Romania, to Paul-Pinchas (1889–1948) and Sima (née Grünfeld, 1895–1990) Blau, who also had a son, Jehoshua. Theirs was an affluent Jewish family. Paul Blau had a doctorate in international relations and worked as a journalist and businessman, while Sima was a homemaker. In 1931 the family moved to Baden, Austria, relocating to Vienna in 1937. One year later, in response to the Anschluss, the Blaus immigrated to Mandatory Palestine.

Upon her arrival in Tel Aviv Clara enrolled in a teachers’ college and later worked as a teacher in a primary school for seven years. Listening to Yeshayahu Leibowitz (1903–1994) lecture in 1945 inspired her to study biology at the Hebrew University of Jerusalem. In 1946 she married Zalman Heyn (1914–1995), the first spokesman and head of public relations at the Ministry of Labor. Their daughter Adith (later Appelbaum) was born in 1950 and Pinhas, their son, was born in 1955.

The War of Independence (1947–1949) interrupted Heyn’s academic studies and she served in the Haganah and in the Israel Defense Forces. Returning to academic life, she completed her M.Sc. in botany (cytotaxonomy) in 1954 under the advisorship of Naomi Feinbrun. In 1960 she submitted her dissertation on the “Monographic revision of annual species of Medicago L. in the sections Spirocarpos Ser. and Orbiculares Urb.” Her book, based on that dissertation, quickly attracted international acclaim and remains a classic to this very day. The family Leguminosae, and especially the genus Medicago, continued to be her main area of expertise. In addition to Medicago, some of the genera she studied in depth were Trigonella, Lotus, Onobrychys, Lupinus, Prangos, Heptaptera and Calendula.

Heyn joined the staff at the Hebrew University of Jerusalem in 1962 and was promoted to full professor in 1978. An excellent and popular teacher, she never left the classroom until the last student had departed. For almost three decades (1969–1997) she directed the Hebrew University’s Herbarium and in 1980 launched the computerization of this herbarium’s collections.

Heyn was invited to join many academic boards and committees throughout Israel and served as an active leader and thoughtful member. In 1974 she was among the founders of the international organization of the Mediterranean Sea botanists, Optima, continuing to serve on its board and executive council until 1993. In 1995 she won Optima’s gold medal, honoring her scientific contributions to the phytotaxonomy of the Mediterranean area.

Heyn’s primary fields of interest were the systematic and evolution of plants, but in the mid–1980s pollination biology caught her eye. In addition, she considered bryophytes her hobby and began studying the mosses of Israel, an interest that peaked in 1978 and on which she collaborated with her former student and long-time research partner Dr. Ilana Herrnstadt. Heyn planned to focus her efforts on this hobby after her retirement.

After a courageous battle with cancer, Clara Heyn passed away on December 27, 1998. Until her last days, she scribbled the finishing touches on the final manuscript of the Bryophyte flora, written together with Israeli colleagues. The memory of her wisdom and humor lives on in the wide circle of close friends, colleagues, students and family. Three taxa bear her name: Medicago sect. Heynianae Greuter; Medicago Heynianae Greuter; and Prangus subg. Heynia Pimenov & V. H. Tikhom.

A chronological list of her scientific publications in English can be found in Flora Mediterranea (1999) 9:13–16.

The Annual Species of Medicago. Jerusalem: Magnes Press, 1963.

The Bryophyte flora of Israel and adjacent regions. Jerusalem: Israel Academy of Sciences and Humanities, 2004.