That sounds pretty awful, doesn't it: ammoniacal nectar? And it doesn't improve if you add to it an alkaline taste. In this apparently our human taste experience is quite similar to that of ants and the like that might otherwise if Toothwort's nectar were sweeter make a beeline to 'rob' this ground-hugging, parasitical plant not leaving enough for Bumblebees. Those little animals are too small to assist in seed production by way of that high-hanging pistil. But Bumblebees are just the right size for their backs to dust pollen onto Toothwort's pistil. Bumblebees - so I've learned from some scientific papers - don't mind that ammoniacal-alkaline taste. So they've got that nectar all to themselves.
Purple Toothwort is a parasite. If you examine it carefully you will find no green leaves - and thus no chlorophyll for energy - but only white tuberous 'suckers' which underground attach to to the roots of deciduous trees such as Poplars and Willows (but also others) from which they draw sugary nutrients especially in Spring. Once seed is formed with the help of our Bumblebees the plant will 'shoot' it away. With luck it will germinate and bring forth these Purple flowers after as long as a decade. The Hortus has three clumps of them in a shady area.
Tags: Hortus Botanicus, Amsterdam, The Netherlands Bumblebee Ants Poplar Willow deciduous trees Purple Toothwort ammoniacal nectar alkaline parasite chlorophyll pollen pistil seed Lathraea clandestina