Three years ago I posted a photo of this flower still in bud (www.flickr.com/photos/87453322@N00/45799333455/in/photoli...). The darkness of January is today upon us as it was then but this photo shows the flowers more fully. Something of a gift on this first day of the opening of the Hortus after our strict lockdown.
Since 2019 I've learned a bit more about the history of our plant and its first describers. On the basis of their scientific description in 1914, I gathered it had been collected in July 1910 by Perrier de la Bâthie himself; but possibly those words are by Raymond-Hamet, Perrier's co-author. Another source says it had been sent to Perrier by the collector-duo Madame and Monsieur Daigremont; and thus it was named for them.
Joseph Marie Henry Alfred Perrrier de la Bâthie (1873-1958) was indeed an intrepid plant collector himself. He'd made his way to Madagascar in the wake of France's annexation of that island in 1896 (after the long Franco-Hova colonial wars since 1883). Initially he was a geologist ( in search of gold). Later he became an adviser to the colonial authorities about anything to do with nature. He is today known as a naturalist and also a conservationist, But much as he loved nature, he attempted to set it to colonial standards. He went so far as to introduce an insect, a cochinella, Dactylopius sp., to southern Madagascar in 1923 to eradicate Opuntia raketa (Prickly Pear) that made colonial farming difficult. The native population, though, needed that plant as fodder for their cattle. The plant gone, a terrible famine ensued killing half of the indigenous people of the area.
It's a chilling history described in detail by Karen Middleton, 'Who killed Malagasy Cactus?', Ethnohistory 25 (1999), 215-248.