摘要:

Cotyledon venation patterns are described for 93 species representing all tribes of the Caesalpinioideae. Patterns are grouped into a series of levels of complexity according to the number of primary veins, nine, seven, six, five, three or one, but five‐ and three‐vein patterns predominate. The number of petiolar vascular strands varies from one to eight but most species have two or four strands. It is proposed that all the patterns have been derived from one in which four strands and a protoxylem trace in the petiole branch and anastomose to form seven primary veins in the lamina. Venation patterns show correlations with cotyledon anatomy, size and shape and with taxonomic grouping at tribal, infratribal and generic levels. Each tribe is characterized by a particular set of related patterns, pattern frequencies and evolutionary tre

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1985.tb02202.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Two new wild potato species from Bolivia, belonging toSolanumsectionPetotaare described.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1985.tb02203.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

FemaleOsyris quadripartitaplants exhibit uninterrupted reproductive activity throughout the year, due to the long duration of successive stages in the cycle and marked within‐crop developmental asynchrony. Cycles corresponding to the flowering seasons of consecutive years overlap in each individual. Flowering takes place in spring, and fruits develop in the dry summer season and ripen at any time of the year. Variation in flowering time explains a negligible proportion of variation in ripening time. The greatest reproductive losses are incurred in the phase extending from closed flowers through unripe fruits, mostly due to ovary abortion. Only 30% of closed flowers eventually reach this latter stage. In contrast, 75% of unripe fruits complete their development, with subsequent dispersal of seeds. The probability of the setting of ripe fruit steadily decreases from early to late season flowers, due to increased ovary abortion rates. Resource limitation in the dry summer season seems responsible for this pattern of selective fruit maturatio

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1985.tb02204.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

In many ornithophilous Loranthaceae pollination is accompanied by an explosive opening of the flowers, and diverse mechanisms have evolved in different genera to bring this about. These are described for the African generaErianthemum, Englerina, Tapinanthus, Globimetula, VanwykiaandPlicosepalus.In many genera tensions within the stamens cause the tubular corolla to split along the petal junctions to form window‐like fenestrae. The flowers are pollinated mainly by sunbirds which insert their beaks through the fenestrae in search of the abundant nectar. This action causes the tube to split and the stamens to coil inwards explosively. InGlobimetulaand many species ofTapinanthuspigment is secreted along the edges of the specialized petal segments of the head, the spathulae. Probing along these secretory junctions causes the spathulae to reflex; further probing splits the corolla tube, and allows the stamens to coil inwards explosively. InGlobimetulareflexure of the petals exposes the central column of stamens, between which secondary fenestrae are developed. InPlicosepaluscurvature of the corolla tube is connected with a more specialized fenestral structure; flower opening is not explosive, and the open flowers continue to be visited regularly by sunbirds. InVanwykiaan early stage in the development of explosive flower‐opening is fo

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1985.tb02205.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Flower colour changes from white or yellow to various shades of red at or near the sites of harvestable pollen inCalytrix glutinosa, Grevillea pilulifera, Isopogon dubiusandPetrophile biloba, and over most of the flower inHypocalymma angustifolium, Verticordia chrysanthaandV. huegeliiand over the pseudanthium inDarwinia citriodora.All bee, wasp, beetle, fly, butterfly and moth visitors select flowers in the white/yellow phase rather than the red or intermediate phase.Nectar is produced by five species, harvestable pollen by four species and detectable perfume by three species, all of which features are usually absent from the red phase. The timing of the colour change in all species also corresponds to loss of stigma receptivity, completion of pollination and onset of ovule seed) swelling. Six species also undergo minor morphometric changes which discourage visitation. In all species, colour change is non‐inducible by pollinators, taking 2–30 days to complete. In three protandrous species, all available pollen may be removed in the first visit, requiring transport of non‐self pollen to rewardless flowers during the 10 h period of the yellow phase.These species are highly floriferous and occur in dense patches. Since only a small proportion of flowers may be receptive at any one time, it is concluded that retention of flower parts essentially serves to enhance long‐distance attraction, while colour change maximizes pollination and foraging eff

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1985.tb02206.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY