Pollinium structure in periplocoideae (apocynaceae)

Numerical Taxonomy of the Asclepiadaceae s.l.

“…Later, Schlechter (1924) re-iterated in more detail the distinctness of the Periplocaceae. In doing so, Schlechter left only Schumann's (1895) Cynanchoideae within the boundaries of the Asclepiadaceae sensu stricto, but his views were accepted by some subsequent authors, e.g., Dave & Kuriachen (1991); Nilsson et al (1993) and Kunze (1996) and refused by others who recognized three subfamilies (Asclepiadoideae, Periplocoideae and Secamonoideae) in the family, e.g., Liede & Albers (1994), Swarupanandan et al (1996), Verhoeven & Venter (1998) and Meve & Liede-Schumann (2004).…”

“…Anthers are invariably two-lobed and each anther lobe contains a number of separate tetrads of different configurations, or one, two or four pollen masses (pollinia) exhibiting a wide range of shapes and sizes (El-Gazzar & Hamza, 1973;El-Gazzar et al, 1974;Schill &Jäkel, 1978 andSreenath et al, 2012); none of the species has as yet been reported to have pollen monads. The free pollinia of ten Asian genera of the Periplocoideae and the separate tetrads in the rest of the subfamily are shed on a translator consisting of a spoon, stalk and an adhesive disc (Verhoeven & Venter, 1998). In contrast, the pollinia of adjacent anthers in the rest of the Asclepiadaceae s.l.…”

“…are attached to each other through a pair of caudicles which are in turn attached to a corpuscle at one of the four or five corners of the stigma. Furthermore, in members of the Asclepiadoideae each pollinium is enveloped by a thin common membrane, whereas in the ten Asian genera of the Periplocoideae with pollinia (Verhoeven & Venter, 1998) and in the Secamonoideae (Endress & Bruyns, 2000), this common membrane is lacking. Thus, in species with pollinia, the flower contains five pollinial ADEL EL-GAZZAR et al…”

“…apparatus each consisting of one or two pairs of pollinia (each from a different anther), a pair of caudicles and a common corpuscle. Caudicles and corpuscles are either pale and soft (in the Secamonoideae) or dark and horny in the Asclepiadoideae (El-Gazzar & Hamza, 1973;El-Gazzar et al, 1974 andVerhoeven &Venter, 1998).…”

Vessel grouping patterns in subfamilies Apocynoideae and Periplocoideae confirm phylogenetic value of wood structure within Apocynaceae

“…1), and can be distinguished by their dextrorsely contorted corolla lobes in bud, specialized anthers adnate to the style head forming a gynostegium, and usually dry follicles with comose seeds (Endress and Bruyns, 2000). With respect to Asclepiadaceae, periplocoids were elevated for the first time to the family level by Schlechter (1905) based mainly on the lack of lignified guide‐rails on the anthers, the spoon‐like structure of the translators and the erroneous assumption that periplocoid pollen is never gathered into pollinia (Verhoeven and Venter, 1998). The distinct pollination mechanism combined with erroneously interpreted morphological characters led Wanntorp (1988) to conclude that the most recent common ancestor of Periplocoideae was to be found in basal Rauvolfioideae, rather than in the derived clades of the group.…”