Phylogenetic relationships were reconstructed among 59 of 77 genera of subfamily Apocynoideae and exemplars of Periplocoideae, Secamonoideae, and Asclepiadoideae (collectively the APSA clade) using sequences from four regions of the chloroplast genome (trnL intron and trnL-trnF spacer, rpl16 intron, rps16 intron, matK and 3′ half of trnK intron) and 16 morphological characters. Apocynoideae are resolved as paraphyletic. The five tribes recognized within this subfamily in the classification of Endress and Bruyns are all paraphyletic or polyphyletic. Seven major clades of Apocynoideae are identified. The first three include genera classified predominantly in tribes Wrightieae and Malouetieae sensu Endress and Bruyns and form a paraphyletic grade to a crown clade. The crown clade includes four clades of Apocynoideae genera classified in tribes Apocyneae, Mesechiteae, and Echiteae together with Periplocoideae, Secamonoideae, and Asclepiadoideae; the latter three constitute the traditional Asclepiadac...

https://bioone.org/journals/Annals-of-the-Missouri-Botanical-Garden/volume-94/issue-2/0026-6493(2007)94[324:POAATA]2.0.CO;2/PHYLOGENY-OF-APOCYNOIDEAE-AND-THE-APSA-CLADE-APOCYNACEAE-SL1/10.3417/0026-6493(2007)94[324:POAATA]2.0.CO;2.pdf

Phylogeny of apocynoideae and the apsa clade (apocynaceae s.l.)1

The Floral Morphology of Secamone and the Evolution of the Pollinating Apparatus in Asclepiadaceae

Da in den letzten Jahren die Beobachtungen uber ein einkerniges Tapetum weiter zugenommen haben, liegt die Vermutung nahe, das dieses eine weitere Verbreitung hat, als bisher angenommen wurde. In der vorliegenden Arbeit wurden zur Prufung der jungst aufgeworfenen Frage, ob dem Vorkommen des einkernigen Tapetums eine gewisse systematische Bedeutung zukame, nicht nur die Angaben uber das einkernige Tapetum (vgl. die Zusammenstellung S. 15–17) kritisch gesichtet, sondern auch alle Angaben uber ein mehrkerniges Tapetum gesammelt und beide Vorkommen einander gegenubergestellt (vgl. den systematischen Teil). Es schien auch angezeigt, auf die verschiedenartigen Abweichungen von der normalen Tapetumentwicklung hinzuweisen, da in einzelnen solchen Fallen (bei weiblichen Pflanzen und pollensterilen Apomikten) ein Unterbleiben oder Verzogern von Kernteilungen in den Tapetumzellen beobachtet werden konnte, wodurch eine Einkernigkeit vorgetauscht sein kann. — Das Vorhandensein sowohl eines inneren als auch eines mehrschichtigen Tapetums ist in den vorliegenden Fallen nicht an eine bestimmte Kernzahl geknupft.

Über das Antherentapetum mit besonderer Berücksichtigung seiner Kernzahl

The profusion of terms for floral parts in Asclepias is summarized in tabular form to clarify previous literature. In cases of synonymy, a preferred term is selected. These terms are then used in an illustrated description of the floral morphology and pollination mechanism of a representative species, Asclepias speciosa. THE STUDY of Asclepias has a long history, both because of the plant's diversity of uses (Gaertner, 1979) and the possession of an unusual adaptation to pollinators where the contents of anther sacs form pollinia that become clipped onto pollinator appendages prior to

The floral morphology of asclepias speciosa (asclepiadaceae) in relation to pollination and a clarification in terminology for the genus

Introduction In a previous paper on South African plants, Riley and Hoff (1961) recorded the chromoson~e nuinbers of 39 species of 3 3 genera from 17 families of South African Dicotyledons. The present paper will present chromosome studies on 17 species of A~lonocotyledons most of which were reported at the X International Genetics Congress in Allontreal in 1959. As in the previous work, seeds were allowed to germinate in Petri dishes and slides were prepared from the meristems of the radicals by the squash technique. Several methods of preparation were uscd and will be discussed under the respective species. The seeds of Aristen tbrysiflorn, Freesin hybrids, ~Mornea polystnchyn, Wntso71in nrclernei, W . foul-cadei, and Phyllorachis sngittata were obtained from the National Botanic Gardens of South Africa at I<irstenbosch and those of Or~zithogalz~7n caudntz~7~z from the Botanical Gardens of the University at Uppsala, Sweden. Seeds of the remaining species were reccived from Mr. A. Berg, curator of the Botanical Garden of the University of Pretoria. Some slides were prepared by Mr. V. J. H o e and some by the author but the examination of the slides and the preparation of the illustrations are the sole responsibility of thc author. As in the previous paper, the genera and families follow the classification of Hutchinson (1959). Voucher specimens are being prepared. Observations Lilincene Aspnrngz~s sprengeri Regel. Root tips were fixed in 1 per cent chromic acid and were stained by the Feulgen technique. The chromosomes are mostly of medium length. The diploid number is 60 (Fig. 1) and this number agrees with the results of most other investigators (Darlington and Wylie, 1955; Delay, 1951; Suto, 1936; Sharina and Bhattacharyya, 1957). A. sprezgeri is apparently a hexaploid, as in most of the species of Aspnragz~ that have been studied the sporophytic chroinosorne number is 20. Chloropbytunz lo~zgipedz~?zculntz~7~~ H. 1,. &I. Forbes. Slides were prepared by the technique of Bhaduri and Ghosh (1954) but with the osnlic acid omitted from the fiuative. The chromoson~es are of three sizes, long, medium, and short. They were well spread apart and the somatic number was determined to be 46 (Fig. 2). This nuinber is not in agreement with that reported by de W e t (1957) for this species nor does it agree with the numbers recorded by other authors for other species of the genus. According to Darlington and Wylie (1955), the basic chromosome number is 7 or 8. De W e t found a sporophytic nuinber of 14 in C. lo7~gipedz~1zcz~lntz~~7?. In all other species that have been studied, the 272 71~irnber is 14, 28, 42, or $6, or 16 or 32, except that Strasburger (1888) reported that in C. conzosz~77z (= C. ster7zbergimzurn) most anthers had 12 haploid chroinosoines and only one anther had 14. Because of

Chromosome studies in some south african dicotyledons

The development of the sporangia in the Asclepiadaceae studied is the same in general as in other plants, while there are no indications of the phylogenetic history of the reduction in number. The primary sporogenous cells without further division become the pollen mother cells. The latter divide each into four with the usual phenomena accompanying tetrad division, but through mutual adjustment and the close adherence of the microspores the evidences of grouping are lost.

T. C. Frye

Papers

Development of the Pollen in Some Asclepiadaceae