All Floras      Search Specimen
Login | eFloras Home | Help
IBSC | Family List | Angiospermae | Betulaceae

Alnus Mill.


Description from Flora of China

Trees or shrubs deciduous. Buds stalked with 2(or 3) scales or sessile with several overlapping scales. Leaves usually serrate or dentate, rarely incised or entire. Male inflorescence elongate, pendulous, cylindric, with numerous overlapping bracts, each bract subtending (3 or)4(or 5) bracteoles and 3 flowers; calyx 4-lobed; stamens (1-)4; anthers 2-loculed, thecae connate, apex glabrous. Female inflorescence 1, or 2-numerous in a raceme or panicle, ovoid or ellipsoid, conelike; bracts numerous, overlapping, woody, persistent, apex 5-lobulate, each bract subtending 2 flowers. Nutlets 2 in each bract axil, compressed, with membranous or papery wings. Fl. mainly spring, Alnus formosana and A. nepalensis autumn.

Three or more divergent subgroups (subgenera) of Alnus are often treated as separate genera (J. J. Furlow, J. Arnold Arbor. 71: 1-67. 1990).

Various Alnus species are grown to protect dikes, some are valued for timber, and the roots have nodules with nitrogen-fixing bacteria.

About 40 species: Bangladesh, Bhutan, China, India, Japan, Korea, Nepal, Sikkim; Europe, North and South America; ten species (five endemic) in China.


Related Objects  

Flora of China  
  • PDF File
  • PDF
    Trees and shrubs of the Andes of Ecuador  
  • Alnus acuminata
  • Image/JPEG

    IBSC @
    Browse by
    Search by name

    Specimen Search

    People @ IBSC



     |  eFlora Home |  People Search  |  Help  |  ActKey  |  Hu Cards  |  Glossary  |