Opis: Phytologia, Vol. 45 (Classic Reprint) - Gleason Henry A.

Excerpt from Phytologia, Vol. 45

In 1809 Robert Brown separated a group of genera from the Apocyneae (= Apocynaceae) on the basis that they differed from the remainder of the family in possessing free styles, a gynostegium (i.e. the fusion product of masses and the more or less common presence of an extra whorl of corona attached in various forms to the petals. He named this group the Asclepiadeae. Apart from these differences, the Apocyneae sensu stricto and the then newly emerging Asclepiadeae shared a multitude of tributes, viz. the regular, pentamentous, tetracyclic, and hypogynous flowers, the almost universal presence of latex and the contorted imbrication of petals. Eversince, the Asclepiadeae grew in size to accomodate new genera and species, and their name was subsequently changed by Lindley (1853) to Asclepiadaceae R.Br.

The Asclepiadaceae were first classified by Decaisne (1844) into 5 tribes (Periploceae, Secomoneae, Asclepiadeae, Gonolobeae and Stapelieae) on the basis of pollen structure, with the first tribe having pollen in tetrads while all other 4 tribes are characterized by pollen masses or pollinia. The mechanism of pollen discharge differs also in the Periploceae (where the tetrads are received and dispersed by spathulate translators) than in the rest of the family (where pollinia are attached to grandular secretions known as corpuscles from the 5 corners of the pentagonal stigma via non-cellular cords known as the caudicles or connectors). Decaisne's classification was later accepted in its entirity by subsequent taxonomists (e.g. Lindley 1853). However, the subdivision of Asclepiadaceae ensu Decaisne has undergone a number of alternations involving primarily the hierarchical status of each of the 5 tribes.

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Szczegóły: Phytologia, Vol. 45 (Classic Reprint) - Gleason Henry A.

Nazwa: Phytologia, Vol. 45 (Classic Reprint)
Autor: Gleason Henry A.
Wydawnictwo: FB &c Ltd
Kod paskowy: 9781330678619
Języki: angielski
Ilość stron: 530
Format: 15.2x22.9cm
Oprawa: Miękka

Recenzje: Phytologia, Vol. 45 (Classic Reprint) - Gleason Henry A.