摘要:

SummaryThe origin of the seed‐plant life history, and subsequent diversification of seed morphology, should be considered two independent, fundamentally distinct evolutionary problems. Gametophytic endospory may have arisen paedomorphically from homosporous ancestors, specifically by progenesis in the gametophyte generation. Heterospory and gametophytic unisexuality are not necessarily evolutionary antecedents of endospory; rather, they may have arisen as developmental consequences of endospory. Once seeds existed, their early pattern of diversification was not one of gradual change in form, but of a proliferation of integumentary types differing widely from one another. Subsequently, the morphological spectrum narrowed, with closed integuments eventually prevailing. This two‐stage pattern of diversity suggests an initial phenotypic breakthrough into a largely “empty” adaptive zone, followed by intensified biotic competition as the adaptive zone filled.

ISSN:0040-0262    

DOI:10.2307/1220881

出版商:Wiley    

年代:2019

数据来源: WILEY

摘要:

SummaryThe pollen of the ditypic family Hoplestigmataceae was examined in LM, SEM, and TEM, and in conjunction with floral morphology compared with the orders Boraginales, Ebenales, and Violales, to which this family has been assigned.Hoplestigmahas pollen with 3‐colporate apertures bordered by (six) meridional ridges that are separated by (three) intercolpar concavities. Pollen similar in SEM and TEM is found inBourreriaandEhretiaof the Boraginaceae, and is also common in the Myrtales. However, this pollen type is not known to occur in either the Violales or Ebenales; in addition the bicarpellate ovary with few ovules and sympetalous corolla ofHoplestigmaare not really typical of the Violales, nor is the parietal placentation ofHoplestigmatypical of the Ebenales. AlthoughHoplestigmashares similar pollen, numerous stamens, and many characteristics of the gynoecium with the Myrtales, it differs in having the petals united basally and unitegmic ovules versus distinct petals and bitegmic ovules in Myrtales. Until Hoplestigmataceae is examined for the presence of internal phloem, one of the more definitive characters for Myrtales, we defer to Takhtajan's placement in the Boraginales.

ISSN:0040-0262    

DOI:10.2307/1220882

出版商:Wiley    

年代:2019

数据来源: WILEY

摘要:

SummaryThe morphology ofPhytolacca dodecandra, locally called endod, was examined using herbarium specimens from throughout its natural range in Africa and analyzed by principal component and principal coordinate analyses as well as contour mapping of the coordinate scores.Phytolacca dodecandrawas also compared toP. dioica(introduced),P. goudotii, P. nutans, andP. octandra(introduced).Phytolacca goudotiiwas found to be scarcely distinct fromP. dodecandra.The status ofP. nutansremains questionable since only the type specimen had extremely long male flower pedicels and no other specimens have been found from throughout Africa with such long pedicels. Examination of P.dodecandrafrom throughout its range in Africa revealed that a few pubescent‐leaved plants were found from Ethiopia. These plants include a strain (Type 44) previously selected for agronomic research.Phytolacca dodecandrawas found to be very variable in its morphology, both within a region and among regions. Major regional trends discovered were differentiation of: 1) the east and west Africa populations; 2) Madagascar plants from the mainland populations; 3) the Gabon plants from other West African plants; and 4) the Uganda, Burundi, Zimbabwe, and South African plants from other regions. No evidence was found to support the recognition of varietiesapiculataEngl. andbrevipedicellataH. Walt.

ISSN:0040-0262    

DOI:10.2307/1220883

出版商:Wiley    

年代:2019

数据来源: WILEY

摘要:

SummaryA computerized database is being developed for the flora of Mount Kinabalu (northern Borneo). The methodology for its development and management is described. The data can be manipulated to produce enumerations (checklists), determination lists, itineraries, specimen citations, exsiccatae lists, annotation labels, type specimen registers, distribution maps, and otherwise queried on‐line at independent work stations or through a network. With minor modifications the system could be adapted for other floristic projects and for general computerization of herbarium specimens.

ISSN:0040-0262    

DOI:10.2307/1220884

出版商:Wiley    

年代:2019

数据来源: WILEY

摘要:

SummaryCommelina carolinianaWalter is the correct name for a species that has often been confused withC. diffusaN. L. Burm. in the southeastern United States. It is lectotypified by a specimen in the Walter Herbarium. The North American plants ofC. carolinianaare conspecific with plants ofC. hasskarliiC. B. Clarke from India. BecauseC. carolinianawas published almost 100 years before Clarke's binomial, it must be taken up as the correct name for the Indian species.Commelina carolinianawas probably introduced into the United States in South Carolina with rice seed from India.

ISSN:0040-0262    

DOI:10.2307/1220885

出版商:Wiley    

年代:2019

数据来源: WILEY

摘要:

SummaryThe red algaSchizymenia dawsoniiAbbott has been found to have both vegetative and reproductive features that link it closely with the widespread tropical/subtropical genusSebdeniaBerthold. The new binomialSebdenia dawsonii(Abbott) comb. nov. is proposed.

ISSN:0040-0262    

DOI:10.2307/1220886

出版商:Wiley    

年代:2019

数据来源: WILEY

ISSN:0040-0262    

DOI:10.2307/1220887

出版商:Wiley    

年代:2019

数据来源: WILEY

ISSN:0040-0262    

DOI:10.2307/1220888

出版商:Wiley    

年代:2019

数据来源: WILEY

ISSN:0040-0262    

DOI:10.2307/1220889

出版商:Wiley    

年代:2019

数据来源: WILEY

ISSN:0040-0262    

DOI:10.2307/1220890

出版商:Wiley    

年代:2019

数据来源: WILEY