Black Alder is monoecious, that is, it has both male and female flowers on the same plant. Pollen is transmitted from male to female via wind.
In this case, the male catkins, or ament, are seen on the left, and the female strobili are on the right. |
| Alder is particularly noted for its important symbiotic relationship with
Frankia alni, actinomycete filamentous nitrogen-fixing bacterium. This
bacterium is found in the root nodules, where it absorbs nitrogen from the
air and makes it available to the tree. Alder, in turn, provides the
bacterium with carbon, which it produces by scrubbing CO2 from the
atmosphere through photosynthesis. As a result of this mutually-beneficial
relationship, alder improves the fertility of the soils where it grows, and
as a pioneer species, it helps provide additional nitrogen for the
succession species which follow. [2]. European Black Alder, a native of Europe, northern Africa, and western Asia, was introduced to North America long ago and has escaped from cultivation, and it is sometimes seen along bodies of water, where it may successfully self-sow and form pure stands. Today, it is grown as a shade tree in urban areas, or at wet sites (ponds, creeks, drainage ditches, etc.) where it thrives and provides both erosion control and ornamental appeal.
European Black Alder is adaptable to a wide range of favorable or harsh environmental conditions. It prefers moist to wet soils of variable pH that are rich and deep, but adapts to average or poor soils that are dry in summer. Growth is especially rapid in occasionally wet to permanently wet areas, such as floodplains , streambanks, and ditches. |
European Black Alder has a leaf that is atypical as compared to other Alders in that it is round in shape, rather than elliptical. In addition, some leaves have a distinct notch at the apex, which is not obvious until the leaves are fully expanded. | - Native:
- AFRICA
Northern Africa: Algeria; Morocco; Tunisia - ASIA-TEMPERATE
Western Asia: Iran; Turkey
Caucasus: Russian Federation - Ciscaucasia
Siberia: Russian Federation - Western Siberia
Soviet Middle Asia: Kazakhstan - EUROPE
Northern Europe: Denmark; Finland; Ireland; Norway; Sweden; United Kingdom
Middle Europe: Austria; Belgium; Czechoslovakia; Germany; Hungary; Netherlands; Poland; Switzerland
East Europe: Belarus; Russian Federation - European part; Ukraine [incl. Krym]
Southeastern Europe: Albania; Bulgaria; Greece; Italy; Romania; Yugoslavia
Southwestern Europe: France; Portugal; Spain
| - black alder (Source: F USSR )
- European alder (Source: Dict Gard )
- swartels (Source: Weeds SAfr 2001 ) [Afrikaans]
- check MMPND for additional names in foreign scripts
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| Synonyms: |
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Black Alder Male Catkins |
The fertilized female flowers become cone-like, green fruits by late spring, and as they grow throughout the summer, they often weigh down the branches that support them. In autumn, the seeds are released as the cones open and the remaining structures (called strobiles) persist on the twigs. References
1. USDA, ARS, National Genetic Resources Program. Germplasm Resources Information Network - (GRIN) [Online Database]. National Germplasm Resources Laboratory, Beltsville, Maryland. URL: http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?2448 (31 May 2008) |
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