Betula michauxii
Sponsor
Kindly sponsored by the Banks family in memory of Lawrence Banks CBE DL VMH
Credits
Hugh A. McAllister, Kenneth Ashburner, Paul Bartlett & Martin Deasy (2026)
Recommended citation
McAllister, H. A., Ashburner, K., Bartlett, P. & Deasy M. (2026), 'Betula michauxii' from the website Trees and Shrubs Online (treesandshrubsonline.
Common Names
- Newfoundland Dwarf Birch
- Michaux's Birch
Synonyms
- Betula terra-novae Fernald
- Apterocaryon michauxii (Spach) Opiz
- Betula nana var. michauxii (Spach) Regel
Other taxa in genus
- Betula alleghaniensis
- Betula alnoides
- Betula alnoides
- Betula ashburneri
- Betula bomiensis
- Betula × caerulea
- Betula calcicola
- Betula celtiberica
- Betula chichibuensis
- Betula chinensis
- Betula cordifolia
- Betula corylifolia
- Betula costata
- Betula cylindrostachya
- Betula davurica
- Betula delavayi
- Betula ermanii
- Betula fargesii
- Betula fruticosa
- Betula glandulosa
- Betula globispica
- Betula gmelinii
- Betula grossa
- Betula gynoterminalis
- Betula humilis
- Betula kweichowensis
- Betula lenta
- Betula luminifera
- Betula lutea
- Betula maximowicziana
- Betula medwediewii
- Betula megrelica
- Betula microphylla
- Betula middendorffii
- Betula murrayana
- Betula nana
- Betula nigra
- Betula occidentalis
- Betula ovalifolia
- Betula papyrifera
- Betula pendula
- Betula populifolia
- Betula potaninii
- Betula pumila
- Betula raddeana
- Betula schmidtii
- Betula skvortsovii
- Betula tianschanica
- Betula utilis
- Betula utilis subsp. albosinensis
- Betula utilis subsp. jacquemontii
- Betula utilis subsp. occidentalis
- Betula utilis subsp. utilis
Editorial Note
This TSO article is an edited digest of the species account in Kenneth Ashburner and Hugh McAllister, The Genus Betula: A Taxonomic Revision of Birches (2013; repr. 2016).
Trees and Shrubs Online, 23 June 2026
Shrub with upright habit up to 1 m in height, although given as to 0.5 m in wild. Bark grey to dark brown, not peeling. Twig puberulent and with longer hairs, glandular but hardly resinous, with stipules and bud scales often persisting for more than one year. Petiole to c. 2 mm. Leaf broadly obovate, base cuneate, variably hairy when young, glabrescent, leaf blade to 0.5–1 × 0.5–1.2 cm with 2–3 pairs of veins, margin crenate with rounded teeth. Bud more or less spherical, c. 3 × 1.5 mm, less than twig diameter. Male and female catkins small, erect, male lateral below female on previous year’s long shoots, rarely terminal. Male catkins to 5 (–6) × 2 (–2.5) mm with rounded brown ciliate-margined scales. Fruiting catkins erect, broadly elliptic, to 11 × 4 mm, peduncle very short. Bracts elliptic, ovate, unlobed, each subtending single nutlet. Nutlet less than 2 mm, wing seeming inflated and not distinct from nutlet; style c. 0.5 mm. 2n=28.
Distribution Canada St. Pierre and Miquelon, Newfoundland, Nova Scotia, Quebec
Habitat Wet peaty situations, Sphagnum bogs.
Betula michauxii is very similar in general appearance to B. nana, but upright and even more slender and delicate. It is a species of wet bogs in eastern mainland Canada and Newfoundland, easily distinguished by the absence of lateral lobes to the scales of the fruiting catkin, and by the single nutlet (instead of the usual three) per fruiting catkin scale, each nutlet having a swollen wing so that the wing and nutlet are not distinguishable. It was described by Edouard Spach (1801–1879) from specimens collected in Newfoundland. Its distribution overlaps with that of B. glandulosa (Furlow 1997), but the two taxa remain distinct and no hybrids have been reported – perhaps because B. michauxii grows in wetter habitats.
Betula michauxii makes a neater, more upright plant than most forms of B. nana. It has small leaves which develop good autumn colour. Although apparently an inhabitant of peat bogs in the wild, it grows reasonably well in ordinary garden soil that is not allowed to dry out. Surprisingly, it will even grow quite well on wet calcareous clay, though in such situations the leaves are liable to become rather chlorotic late in the season.