The recent start of a project aiming at a complete digitization of the Z+ZT Herbarium collections constitutes a wonderful opportunity to rediscover hidden or long-forgotten treasures. It was somehow by chance that I came lately across a fantastic specimen of the bell-flower family, which could, no more no less, represent one of the smallest flowering plant species in the world… This remarkable discovery immediately reminded me of a study published in 2015 by Sylvester and collaborators in the journal Taxon, and for which I was asked to act as an associate-editor. I was eventually able to observe what I could hardly believe after my first reading of the paper! Many tiny specimens, up to 3-4 mm high, patiently glued on a piece of paper, so as to constitute the absolute reference specimen (or "type") of a new species called Lysipomia mitsyae.
The plant is actually so small that there is "barely any space left", so to say, to produce leaves and stems… Only a flower borne by a root system and persistent cotyledons! Given the lack of morphological diagnostic characters, it was extremely difficult to undisputedly place the specimen in a botanical family, not even to mention a genus, without the help of molecular tools. Today, we know with confidence that the mysterious plant belongs to the genus Lysipomia of the Campanulaceae-Lobelioideae, a group relatively frequent in the Peruvian Andes, where the new species remained yet unnoticed until 2012!
Could Lysipomia mitsyae represent the smallest flowering plant (angiosperm) in the world? There are actually smaller aquatic plants such as the duckweed genus Wolffia (Araceae), but as far terrestrial forms are concerned Lysipomia mitsyae would certainly come first! As other contenders for the title of "smallest land angiosperm" one can cite the dwarf mistletoe Arceuthobium minutissimum (Santalaceae), a parasite from the Himalayan Mountains, the Peruvian violet Viola lilliputana (Violaceae), or minute annuals such as Crassula closiana (Crassulaceae) or Cicendia quadrangularis (Gentianaceae). Interestingly, a vast majority of these vegetal dwarves are found in the high-elevation grasslands of the Andes, a potential "hotspot for minuscule plants".
There is, so far I know, no official entries for "plant world records" in the famous Guinness Book, and more intensive literature survey would certainly be necessary before deciding which species, if any, may actually be considered the world’s smallest land angiosperm. One thing is sure though: Lysipomia mitsyae is indisputably the smallest member of the bell-flower family, an amazing group of plants that also contains true trees!
Guilhem Mansion
Reference
Sylvester, SP; Quandt, D; Ammann, L; Kessler, M (2016). The world's smallest Campanulaceae: Lysipomia mitsyae sp. nov. Taxon, 65(2):305-314.
Specimen diagnose
Lysipomia mitsyae Sylvester & D.Quandt, sp. nov. – Holotype: PERU. Cuzco, Provincia Calca, Distrito Calca, grazed ground below the SW facing crags of the Laguna Yanacocha, 1.5 km E of Cancha Cancha village, Huarán, 4340 m, 13°14′28.4″S, 72°01′16.8″W, 27 March 2012 (flowers and fruits), S.P. Sylvester 1417 (USM No. USM285670; isotypes: Z+ZT, barcode Z-000099206).
