摘要:

The generaCorynantheandPausinystaliaare an easily recognizable group within the tribe Coptosapelteae because the corolla lobes are provided with a distinct spherical, club‐shaped or linear appendage. In the past the delimitation of the species and the 1–3 genera in the literature has been problematical. A short revision of the group is undertaken, based mainly on a study of Central African herbarium specimens. The morphological features of the group are reviewed and documented. Stipules were commonly found to have interlocking vernation; this type of ptyxis has not yet been reported from the Rubiaceae. Characters and their states are coded for a numerical phenetic and cladistic analysis of the relationships among the species. Our formal analyses corroborate the view that two genera can be recognized,Corynanthe(characterized by exserted style and anthers, undivided stigma and mainly loculicidal capsule; three species) andPausinystalia(characterized by style and anthers included in the corolla tube, a bilobed stigma and predominantly septicidal capsule; five species). The entire group probably evolved from aCorynanthe‐like ancestor; a drastic shift in flower biology, viz. the loss of secondary pollen presentation, probably correlated with adaptations to another pollinator which may have caused the divergence between the two genera. These show the characteristic distribution pattern of strict rain forest groups in Africa, except that they are missing from the lowland forests of the Zaire Basin. The species are concentrated around the known forest refugia of the quaternary glaciation: onlyC. pachycerasis distributed in almost the whole rain forest area. A formal taxonomic treatment (with key to species) of the two genera is given; a key to the genera of the Coptosapelteae of the African continent is also included. The examination of the isotypes of forgotten names described by the Berlin school revealed three new synonyms.Pausinystalia angolensisdescribed from Cabinda (Angola) by Wernham is proved to be synonymous withP. macroceras. A few other taxonomic changes are made.Pausinystalia iturienseDe Wild, is reduced to a subspecies ofP. lane‐poolei(Hutch.) Hutch, ex Lane‐Poole;P. brachylhyrsum(K. Schum.) W. Brandt is recognized again (instead of being reduced to a form of P.macroceras(K Schum.) Pierre ex Beille),P. talbotiiWernham is maintained inPausinystalia, and not transferred toCoiynanthe, as recently

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1996.tb00485.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

A modified classification of the family Asclepiadaceae R. Br.s.s. into three tribes – Secamoneae, Asclepiadeaes.l. and Stapelieaes.l. – is proposed. The position of attachment of the caudicles to the pollinia is suggested as a criterion for defining the erect and pendulous stature of the pollinaria. The concept of the transverse stature of pollinaria has been abandoned. In addition to the stature of the pollinaria, the morphology of the anther sacs (whether or not embedded in the tissue of the anther wings) and the position of anther wings with respect to the anther sacs are suggested as supplementary characters for tribal classification of the family. The characters of the gynoecium, particularly the presence or absence of true styles and the sharp constriction between stigma‐head and ovaries (i.e. clavuncular morphology) have also been suggested as useful in differentiating Asclepiadeaes.l. and Stapelieaes.l, along with the stature of the pollinaria. The circumscription of Asclepiadeae is emended to accommodate taxa of the former tribe Gonolobeae as a subtribe. The circumscription of Stapelieae has been retained in a wider sense, as suggested by Decaisne (1844). The tribes Fockeeae Kunze, Liede&Meve (1994), Marsdenieae Benth. (1876), Ceropegieae Benth. (1876), and Stapelieaes.s. sensuBenth. (1876; non Decne., 1844) have been relegated to subtribe status in the tribe Stapelieae Decne. (1844). Homology of the different parts of the gynoecium in the Asclepiadeae(s.l.)with those in the Stapelieae (s.l.) has been drawn. Segments of the style have been distinguished into ‘true style’ and ‘pseudostyle’, the former as parts of the ovary segment in development, the latter as stigma segment in development. The genusTybphoraR. Br. which was formerly treated under Stapelieae Decne. has been transferred to Asclepiadeae based on the morphology of the pollinaria, gynoecium and seed coat

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1996.tb00486.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

The accord between symmetries of flower shape (external contours) and nectar guides (internal contours) was examined using the bulbous flora of South Africa, and in the general floras of Britain, Alpine Colorado, Canadian Arctic and Israel. It was found that radially symmetrical flowers have radially symmetrical nectar guides whereas bilaterally symmetrical flowers have bilaterally symmetrical nectar guides. It is suggested that the complementarity between the external and the internal contours of the flower increases the probability that, and efficiency with which, a bee moves into the flower's centre and towards the sporophylls and access to floral rewards, regardless of the flower's form and the bee's previous experience. Patterns of coloration of tepals against background and nectar guides against tepals also accord with behavioural and sensory characteristics of pollinators. It is suggested that the complementarity of contours is probably constrained by floral development, but patterns of coloration of tepals against background and nectar guides against tepals is constrained by pollinators' sensory physiology.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1996.tb00487.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

The fruit and seed anatomy and morphology ofAkania bidwillii, the monotypic genus in the Akaniaceae, have been studied in an effort to clarify its systematic position. The loculicidal (1,2‐) 3‐locular fruit with Ugnified fibrous 6–7‐layered endocarp is clearly of capsular type. Seedsof Akaniaare relatively large, smelling of bitter almonds, abundantly albuminous, with straight dicotyledonous embryo. The seed coat ofAkaniais exo‐mesotestal with fully obliterated tegmen in early stages; 1‐layered exotesta represented by columellar thick‐walled cells with numerous invaginations of inner cell walls; mesotesta 25–35‐layered, composed of thick‐walled, but not lignified mostly rounded sclereids filled with tanninlike substances, the innermost part of mesotesta is aerenchymatous, sometimes collapsed, and traversed by 6(8) postchalazal vascular bundles, 2–3 layers of endotesta composed of enlarged cuboid cells with heavily thickened walls. Evidence mainly from seed morphology and anatomy of seed coats emphasizes the anomaly of the traditional inclusion of Ankaniaceae in the Sapindales, being quite distinct in spermoderm structure and origin from both Sapindaceae and Staphyleaceae in particular as well as from other families of the order, excepting somewhat anomalous exo‐mesotestal Bretschneideraceae. Furthermore, seed anatomy does not confirm any relationships with Capparales. It is suggested that Akaniaceae together with Bretschneideraceae constitute a distinct relict side‐branch of connaraceous‐sapindaceous ancestry tracing back to primitive exo‐mesotestal Resales. On the basis of available data of seed coat anatomy it is appropriate to remove archaic Akaniaceae with Bretschneideraceae from more advanced Sapindales. Furthermore, widi the addition of more data on carpology and seed anatomy of basal Rosidae the systematic position of the family should be redefined in terms of its primitiveness and the lack of close

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1996.tb00488.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY