Asclepiasspeciosa (Apocynaceae, Asclepiadoideae): a rare o

What this paper is about

While surveying invasive common milkweed in Lithuania, the authors found showy milkweed, the western North American species, growing wild. It is the first European record.

A herbarium check showed it had been collected in Lithuania as long ago as 1962 and filed as common milkweed, so it may be overlooked rather than new.

Summarised here from the abstract below. Not the authors’ words.

Abstract

Studies on populations of Asclepiassyriaca L. in Lithuania revealed the occurrence of a new alien plant species, the North American native Asclepiasspeciosa Torr. (Apocynaceae, Asclepiadoideae), in southern parts of Lithuania - the first report of the latter species in Europe. Interestingly, a thorough analysis of herbarium specimens revealed that A.speciosa had first been collected in Lithuania in 1962, but the specimen was misidentified at the time as A.syriaca. The newly discovered population of A.speciosa occupies mesic grasslands, tall-herb fringe communities and arable field habitats. Sexual reproduction of this species was not recorded; it spreads locally by means of vegetative reproduction. We present here an exhaustive analysis of morphological characteristics and differences between A.speciosa and A.syriaca and other species of the genus, as well as a key for identification of alien Asclepias species in Europe. We predict that the effect of A.speciosa on native habitats and communities, and its economic impact, are comparable to those of the highly invasive A.syriaca. Although A.speciosa currently occurs very rarely as an alien species in Europe, its existence in other regions of Europe is highly probable.

Abstract reproduced from the published paper, which is licensed CC BY. Copyright remains with the authors.

Key terms

EcologyMorphologyReproductionIdentificationAlien speciesInvasivenessNaturalization

Milkweeds in this paper

Common Milkweed Asclepias syriaca
Showy Milkweed Asclepias speciosa

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APA

Milkweed USA. (2026). Asclepiasspeciosa (Apocynaceae, Asclepiadoideae): a rare or unrecognized alien species in Europe? (listing). Retrieved DATE, from https://milkweedusa.com/research/asclepiasspeciosa-apocynaceae-asclepiadoideae-a-rare-or-unrecognized-alien-species-2019/

MLA

"Asclepiasspeciosa (Apocynaceae, Asclepiadoideae): a rare or unrecognized alien species in Europe? (listing)." Milkweed USA, 2026, https://milkweedusa.com/research/asclepiasspeciosa-apocynaceae-asclepiadoideae-a-rare-or-unrecognized-alien-species-2019/. Accessed DATE.

Chicago

Milkweed USA. "Asclepiasspeciosa (Apocynaceae, Asclepiadoideae): a rare or unrecognized alien species in Europe? (listing)." Last modified 2026-08-01. Accessed DATE. https://milkweedusa.com/research/asclepiasspeciosa-apocynaceae-asclepiadoideae-a-rare-or-unrecognized-alien-species-2019/.

BibTeX

@misc{milkweedusa_researchasclepiasspeciosaapo,
  title  = {Asclepiasspeciosa (Apocynaceae, Asclepiadoideae): a rare or unrecognized alien species in Europe? (listing)},
  author = {{Milkweed USA}},
  year   = {2026},
  url    = {https://milkweedusa.com/research/asclepiasspeciosa-apocynaceae-asclepiadoideae-a-rare-or-unrecognized-alien-species-2019/},
  note   = {Accessed DATE}
}