| (Margaret (Margret) Constance) Helen Blackler | |
| Birth Date: | 29 August 1902 |
| Birth Place: | Arnside, Cumbria, England |
| Death Place: | St Andrews, Scotland |
| Fields: | Phycology |
| Workplaces: | Liverpool Museum University of St Andrews |
| Alma Mater: | University of Liverpool |
| Thesis Title: | A morphological and cytological study of certain species of Asperococcus |
| Thesis Year: | 1928 |
| Doctoral Advisor: | Margery Knight |
Margaret Constance Helen Blackler (1902–1981) was a British phycologist, botanical collector and museum curator.
Blackler was Assistant Keeper of Botany at Liverpool Museum between 1933 and 1945. She also had some temporary teaching posts at colleges and the universities of Liverpool and Sheffield. In 1947 she moved to an academic post at University of St Andrews. She was a lecturer in botany until 1961 and then promoted to senior lecturer until her retirement in 1968. She continued active laboratory research at the university's Gatty Marine Laboratory until the day before her death.
At Liverpool Museum she curated historic plant specimens that had been added to the herbarium. These included ones from Liverpool Botanical Garden and ferns from India and Ceylon. She was also able to work on some collections of marine algae.
Her research at St Andrews was about marine algae, especially brown algae (Phaeophyceae). She focused on taxonomy and ecology, especially in the genera Colpomenia, Pylaiella and Desmarestia.
She spent 1959 in the United States visiting marine biology laboratories and the University of California, Berkeley, with funding from the American Association of University Women.
She was a member of the founding committee of the British Phycological Society and was made an Honorary Life Member in 1977.
Blackler's over 39 scientific publications and books include:
She identified at least 38 specimens of marine algae, particularly of the Scytosiphonaceae species Colpomenia peregrina Sauv. that are now held in the Natural History Museum, United Kingdom.
Margaret Constance Helen Blackler (usually known as Helen Blackler) was born in Arnside, Lake District, United Kingdom, on 29 August 1902. She attended Merchant Taylors' Girls' School in Crosby, Liverpool, and then the University of Liverpool, graduating in 1926 with a B.Sc. degree. She carried out her doctoral research under the supervision of Margery Knight, thus becoming involved with marine algae, and her Ph.D. was awarded in 1928 for her thesis "A Morphological and Cytological Study of Certain Species of Asperococcus". The following year she took a diploma in education.[1]
She died unexpectedly of a heart-attack at St Andrews on 5 November 1981.[2]