Comparative floral structure and systematics of Pelagodoxa and Sommieria (Arecaceae)

Floral structure is compared in Pelagodoxa and Sommieria (Arecaceae, Arecoideae). Male flowers have three free, imbricate sepals, three basally congenitally united and apically valvate petals, and six stamens. Anthers are dorsifixed and dehiscence introrse. The sterile gynoecium is tricarpellate. Female flowers have three free, imbricate sepals and three free, imbricate petals, which are slightly fused with the sepals at the base. Four to six staminodes are congenitally united at the base and fused with the ovary for a short distance. The gynoecium is syncarpous. Carpels are almost equal in early development; later the gynoecium becomes pseudomonomerous. The three stigmatic branches are equally developed, apical and sessile. The carpels are (syn-)ascidiate up to the level of the placenta and (sym-)plicate above. Each carpel has one ovule, in the sterile carpels it is aborted at anthesis. The fertile ovule is erect up to anthesis and pendant afterwards because of the bulging out of the ovary. Pollen tube transmitting tracts (PTTT) encompass the secretory epidermis of the ventral slits of each carpel. Floral structure in Pelagodoxa and Sommieria supports the sister group relationship between the two genera suggested in recent molecular phylogenies and reflects their close relationships to a major clade of pseudomonomerous arecoid palms from the Indo-Pacific region.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 146 , 27–39.     

Seed morphology and anatomy of Austrotaxus spicata (Taxaceae) and its systematic position

The anatomy and ultrastructure of seed envelopes of a New Caledonian endemic Austrotaxus spicata were examined for the first time. The systematic position and phylogenetic relations of Austrotaxus were analysed in light of these data. The structure of aril and spermoderm were investigated to demonstrate the similarities with Phyllocladus as well as with Taxus and Pseudotaxus . On the basis of all female reproductive organ characters, Austrotaxus appeared to be fairly isolated and its placing in the independent family Austrotaxaceae was confirmed from the standpoint of comparative anatomy of the seed coat. Taking into consideration that the heterobathmy of features can be the most distinctively traced in the structure of reproductive organs, evaluating the extent of evolutionary advancement of Austrotaxus seems to be rather difficult. However, it is evident that the relationship of Austrotaxus either with Taxaceae or with Podocarpaceae s.l . is considerably remote.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 145 , 437–443.     

Gynoecium, fruit and seed structure of Paullinieae (Sapindaceae)

Despite an emphasis on fruit characters in Paullinieae taxonomy, few detailed morphological and anatomical studies of the gynoecia, fruits and seeds exist. The aims of the present study were (1) to provide a detailed documentation of gynoecium, fruit and seed structure and ontogeny in selected Paullinieae taxa; (2) to determine whether the gynoecium, seed and seedling provide additional characters of systematic value within the tribe; and (3) to relate the structural findings to mechanisms of fruit dehiscence and dispersal within these taxa. Newly described characters of systematic value within Paullinieae are shape and surface of the obturator, type of pollen tube transmitting tract, indumentum of the inner and outer surface of the carpels, ovary wall anatomy, aril anatomy, pseudo-hilum form, seedling germination mode and structure of first leaves. The fruits of Paullinia are septifragal, and conspicuous colour contrasts between the pericarp, aril and seed in most species of this genus are suggestive of a bird dispersal syndrome. Interestingly, it appears that relatively minor structural changes are associated with switches to rodent dispersal in Paullinia sphaerocarpa and water dispersal in P. clathrata and P. hystrix. Anemochorous fruits are septifragal ( Cardiospermum and Urvillea ) or schizocarpic ( Houssayanthus , Lophostigma , Serjania ). They are structurally similar and Cardiospermum with septifragal capsules may also show septicidal dehiscence.  © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 147 , 159–189.     

Comparative floral structure and systematics in Chrysobalanaceae s.l. (Chrysobalanaceae, Dichapetalaceae, Euphroniaceae, Trigoniaceae; Malpighiales)

Chrysobalanaceae s.l. , one of the few suprafamilial subclades of Malpighiales that is supported by molecular phylogenetic analyses, and containing Chrysobalanaceae, Dichapetalaceae, Euphroniaceae, and Trigoniaceae, was comparatively studied with regard to floral structure. The subclade is well supported by floral structure. Potential synapomorphies for Chrysobalanaceae s.l. are the following shared features: floral cup; flowers obliquely monosymmetric; sepals congenitally united at base; sepals of unequal size (outer two shorter); fertile stamens concentrated on the anterior side of the flower and sometimes united into a strap; staminodes absent in the posteriormost antepetalous position; anthers extremely introrse, with thecae almost in one plane; endothecium continuous over the dorsal side of the connective; dorsal anther pit; gynoecium completely syncarpous up to the stigma; carpel flanks slightly bulged out transversely and thus carpels demarcated from each other by a longitudinal furrow; flowers with dense unicellular, non-lignified hairs, especially on the gynoecium; light-coloured, dense indumentum on young shoots and inflorescences. Potential synapomorphies for Chrysobalanaceae + Euphroniaceae include: spur in floral cup; clawed petals; lignified hairs on petals; nectary without lobes or scales and mostly annular. Potential synapomorphies for Dichapetalaceae + Trigoniaceae include: special mucilage cells in sepals in mesophyll (in addition to epidermis); anthers almost basifixed; gynoecium synascidiate up to lower style; nectary with lobes or scales and semi-annular.  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 157 , 249–309.     

Micromorphology of Scirpus (Cyperaceae) and related genera in south-west Europe

Glume surface, fruit surface, perianth bristles and pollen morphology in Scirpus L. and related genera from south-west Europe have been investigated by light and scanning electron microscopy. The results of this analysis confirm the heterogeneity of the group and provide further support to the current recognition of the genera Scirpus L., Bolboschoenus (Rchb.) Palla , Scirpoides Ség., Schoenoplectus (Rchb.) Palla, Isolepis R.Br., Trichophorum Pers. and Blysmus Panz. as well as to a re-appraisal of subg. Actaeogeton (Rchb.) Oteng-Yeb. of Schoenoplectus .  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 145 , 45–58.     

A new species of Begonia (Begoniaceae) from Guangxi, China

Begonia gigabracteata H.Z. Li & H. Ma sp. nov. ( Begonia section Diploclinium , Begoniaceae) is described and illustrated from North Guangxi Zhuang Autonomous Region, south-west China. Its chromosome number (2 n  = 30) and pollen and seed micromorphology are reported. This species grows in ravines on damp or slightly moist limestone. It is morphologically similar to B. summoglabra T.T. Yü (section Reichenheimia ) and B. labordei H. Lél. (section Diploclinium ). However, it differs by its sparse glandular hairs, number of perianth segments, colour of venation on the abaxial blade, and unique heteromorphous bracts. A line drawing and plate of B. gigabracteata and a photograph of the type of B. summoglabra are presented as an aid to identification.  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 157 , 83–90.     

Seed dormancy in relation to seed storage behaviour in Acer

Dormancy in seeds of Acer opalus is shown to be mainly caused by the seed coats, although a slight embryo dormancy exists in fresh seeds. The ability to germinate after drying indicates that seed storage behaviour is orthodox. Recalcitrant seeds were heavier than orthodox seeds not only within section Acer but also within the whole genus after statistical control of phylogeny, through a phylogenetic ANOVA with data from two different Acer phylogenies. An evolutionary change from orthodox to recalcitrant behaviour is postulated for genus Acer , but this change appears not to have been accompanied by a change in seed dormancy, at least in the taxonomic section in which Acer opalus belongs.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 145 , 203–208.     

Reproductive structures and systematics of Buxaceae

Buxaceae belong to a grade of families near the base of eudicots. Flowers of these families are characterized by a variable number and arrangement of floral organs. In this study, the anthetic structure of the gynoecium and androecium of representatives of all genera of Buxaceae were comparatively studied, and observations on the flowering processes and pollination biology were made. Styloceras and Notobuxus were studied in detail for the first time. Various features of the morphological analysis support our earlier molecular phylogenetic study. Shared reproductive characters among Sarcococca , Pachysandra and Styloceras are the occurrence of two (rarely three) carpels, the lack of interstylar nectaries, a micropyle formed by both integuments, attractive stamens in male flowers, and fleshy fruits. In addition, Styloceras and Pachysandra share a secondary partition in the ovary. Notobuxus does not seem to be clearly distinct from Buxus . Both have a similar inflorescence and perianth structure; female flowers have three carpels, interstylar nectaries, micropyles formed by the inner integument, rudimentary arils, and they develop into capsular fruits; in male flowers stamens are sessile and the central pistillode is lacking in some species. Thus, it is questionable to justify a separation of Buxus and Notobuxus at genus level. The results further strongly support the placement of Buxaceae among basal eudicots.  © The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 140 , 193–228.     

Abortive seed development in Ulmus minor (Ulmaceae)

Three genotypes of field elm ( Ulmus minor ) were studied to determine the structural basis of seed abortion in this species. In the non-abortive control, P-VV1, the pattern of seed development is similar to many flowering plants. The embryo progresses through defined morphological stages leading to developmental arrest as the seed matures. Storage products are abundant within embryo cells. Endosperm development is similar to the nuclear type; however, a more extensive cellularization of the endosperm occurs prior to it being crushed by the expanding embryo. For the abortive genotypes, M-SF1 and V-JR1, abnormalities in endosperm development are found. This is judged by the early cellularization and the massive synthesis of the PAS-positive material in the cellular endosperm. In these abortive genotypes, embryo development is delayed and storage products failed to accumulate within embryo cells. After seed desiccation, no living embryo tissue remains within the seed coat in the abortive genotypes.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 145 , 455–467.     

An unusual case of epigeal cryptocotylar germination in Rollinia salicifolia (Annonaceae)

An unusual case of epigeal cryptocotylar germination found in Rollinia salicifolia Schltdl. (Annonaceae) is described and is discussed in relation to the terminology used for germination studies. The terms cryptocotylar and phanerocotylar are used to describe the permanence of cotyledons within the seed coat or endocarp; the terms epigeal and hypogeal are used to refer the position of cotyledons in relation to ground level. The terms to describe position about ground level and permanence of cotyledons within the seed coat or endocarp are not used simultaneously in many papers, and some authors consider the terms cryptocotylar and hypogeal to be synonyms. Cases of epigeal cryptocotylar germination seem to be scarce in the literature. The morphological characters shown by R. salicifolia seeds and seedlings − a non-chlorophyllous embryo, abundant endosperm, thick woody seed coat, thickened hypocotyl and non-photosynthetic haustorial cotyledons − are closely related to its epigeal cryptocotylar germination. This is the first record of this type of germination in Argentina.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 146 , 53–56.     

Fruits and seeds of Ruppia (Potamogetonaceae) from the Pliocene of Yushe Basin, Shanxi, northern China and their ecological implications

Numerous fruits and seeds of Ruppia are reported from the Upper Pliocene (2.3–3.5 Myr ago) Zhangcun Formation in Yushe Basin, Shanxi, northern China. They are the first fossil Ruppia from China and demonstrate the importance of fruit and seed fossils in recording genera not represented by fossil leaves. These Ruppia are characterized by possessing a small oval endocarp, smooth endocarp surface, distinct elliptical external depressions, distinct apical mucro, slightly curved seed shape and conspicuous globose hilum. A new species, R. yushensis Zhao, Collinson and Li, is described from these endocarp and seed features. Comparison with the two European Miocene species, R. palaeomaritima Negru and R. maritime-miocenica Szafer, indicates the existence at that time of three different geographical and stratigraphical species. R. yushensis constitutes the first Pliocene record of Ruppia and extends the range of fossils of this genus from Europe to eastern Asia. R. yushensis is the only aquatic plant in the uppermost middle part of the Zhangcun Formation. This monotypic occurrence indicates a brackish, clear, tranquil and shallow lake in this region in the Late Pliocene. The smooth endocarp surface further suggests a warm temperate or temperate palaeoclimate.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 145 , 317–329.     

The developmental floral morphology of Montrichardia arborescens (Araceae) revisited

The spadix of Montrichardia arborescens contains unisexual flowers without a perianth. The pistillate flowers are located in the basal portion of the inflorescence, and the staminate flowers are located in the apical portion. There is a narrow :zone between male flowers and female flowers consisting of atypical flowers. The portion of the atypical flowers facing the staminate zone exhibits staminate characters (stamens), and the portion facing the pistillate zone has an aborted gynoecium. The floral development of Montrichurdia is compared with that of Philodendron and a new interpretation of the morphology of atypical flowers of Montrichardia is proposed. Ontogenetic evidence supports relationships with Philodendron rather than Cercestis. 2001 The Linnean Society of London     

Reproductive ecology of the endemic Lecocarpus pinnatifidus (Asteraceae) in an isolated population in the Galápagos Islands

Lecocarpus pinnatifidus is an endemic member of the Asteraceae occurring on only one island in the Galápagos archipelago. The capitula are large with female ray florets and male disc florets. They are self-compatible but this study suggests fruit set is pollen limited. Visits from Xylocopa darwini and other larger insect pollinators are rare, and small insects seem to be the main pollinators. Small insects carry few pollen grains and most likely mediate self-pollinations. Self-compatibility and seed set after selfing are the most common reproductive strategy in the Galápagos Islands and L. pinnatifidus seemingly fits well into this group.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 146 , 171–180.     

Stockwellia quadrifida (Myrtaceae), a new Australian genus and species in the eucalypt group

A new genus and species in the eucalypt group of the Myrtaceae is described. Stockwellia quadrifida D.J. Carr, S.G.M. Carr & B.Hyland gen. et sp. nov. is a rainforest tree of restricted distribution on the Atherton Tableland, North Queensland, Australia. Molecular data suggest that it is the sister taxon to Eucalyptopsis and this is supported by morphological characters. The prolonged hypanthium and reduced perianth appear to be synapomorphies for these two genera and the circumscissile hypanthium a synapomorphy shared with Allosyncarpia . Stockwellia differs from Eucalyptopsis by the distinct, albeit reduced, perianth and the hypanthium splitting into four segments at anthesis. The relationship of these two genera indicates an historical biogeographical link between New Guinea and the Queensland wet tropics region.  © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 139 , 415–421.     

The lichenicolous Opegrapha species (Roccellaceae, Ascomycota) with 3-septate ascospores on Pertusaria and Ochrolechia

The Opegrapha species with 3-septate ascospores growing on Pertusaria and Ochrolechia are revised. Two species are recognized: Opegrapha anomea (of which O. pertusariae , O. quaternella , O. wetmorei and possibly Leciographa weissii are considered to be synonyms), and O. blakii Ertz & Diederich sp. nov. described from a sterile lichen with an Ochrolechia -like thallus, known from Ecuador and Venezuela. Opegrapha anomea and several related lichenicolous species with roundish or irregular, often multilocular ascomata are morphologically intermediate between Opegrapha and Plectocarpon , and might represent a distinct genus.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 144, 235−241.     

Two new species of Sicyos (Cucurbitaceae) from Guerrero and Oaxaca, Mexico

Two new species of Sicyos from Mexico are described and illustrated: Sicyos cordifolius from the state of Guerrero, which belongs to the group with dry, armed fruits, and Sicyos bulbosus from the state of Oaxaca, which belongs to the group with fleshy, unarmed fruits. Sicyos cordifolius is quite different from the rest of the species previously described. Although S. bulbosus is very similar to S. galeottii Cogn., it is clearly different in receptacle shape and size.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 145 , 373–378.     

A new Spanish species of Tragopogon (Asteraceae: Lactuceae)

Tragopogon cazorlanum (Asteraceae: Lactuceae) is proposed as a new Spanish species with distribution restricted to the Baetic mountains (south-eastern Spain). Its morphological, palynological, chromosomal, biogeographical and ecological features are discussed, as well as its main relationships and differences with reference to other Spanish species of the genus.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 146 , 505–511.     

A new species of Arabis (Brassicaceae) from inner Anatolia

A new species of Arabis L., A. erikii Mutlu sp. nov. , is described and illustrated. The species is restricted to inner Anatolia, south-west of Sivas. It grows on steppes. Diagnostic morphological characters are given for discrimination from the most similar taxa.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 145 , 251–256.     

Fruit and seed ontogeny related to the seed behaviour of two tropical species of Caesalpinia (Leguminosae)

Caesalpinia echinata and C. ferrea var. ferrea have different seed behaviours and seed and fruit types. Comparison of the seed ontogeny and anatomy partly explained the differences in seed behaviour between these two species of Brazilian legumes; some differences were also related to fruit development. The seed coat in C. ferrea consisted of two layers of osteosclereids, as well as macrosclereids and fibres, to form a typical legume seed coat, whereas C. echinata had only macrosclereids and fibres. In C. echinata , the developing seed coat had paracytic stomata, a feature rarely found in legume seeds. These seed coat features may account for the low longevity of C. echinata seeds. The embryogeny was similar in both species, with no differences in the relationship between embryo growth and seed growth. The seeds of both species behaved as typical endospermic seeds, despite their different morphological classification (exendospermic orthodox seeds were described for C. echinata and endospermic orthodox seeds for C. ferrea ). Embryo growth in C. ferrea accelerated when the sclerenchyma of the pericarp was developing, whereas embryonic growth in C. echinata was associated with the conclusion of spine and secretory reservoir development in the pericarp. Other features observed included an endothelial layer that secreted mucilage in both species, a nucellar summit, which grew up into the micropyle, and a placental obturator that connected the ovarian tissue to the ovule in C. ferrea . © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 146 , 57–70.     

Morphology of fruits, seeds and embryos of Argentinian Capparis L. (Capparaceae)

Embryos, seeds and fruits of four species of Capparis L. (Capparaceae) from Argentina are described in this paper: C. flexuosa (L.) L. sensu lato, C. retusa Griseb., C. speciosa Griseb. and C. tweediana Eichl. Chlorophyllous embryos are found in C. flexuosa and C. retusa , species with thin seed coats, dehiscent siliques, and somewhat fleshy red endocarps. Nonchlorophyllous embryos are found in the berry-fruited C. speciosa and C. tweediana , the former with leathery indehiscent fruit wall, the latter with thin-walled dehiscent berries with massive fleshy pulp. The pulp is permeated by seed coat hairs in C. tweediana . The embryos of C. flexuosa , C. retusa and C. tweediana belong to the 'Axile Division, Foliate Subdivision, and Folded Type' of the classification devised by A. C. Martin in 1946. Some features of the embryo of C. speciosa (which are not considered in Martin's classification), support a new subdivision (Massive) and a new morphological type (Unequal cotyledons), characterized by profound anisocotyly, globose shape of the major cotyledon, presence of suberized cells and an undeveloped radicle. Anatomical studies of embryos and seedlings confirm the anisocotyly.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 145 , 209−218.