Morphological and ultrastructural variations in Scliizjaea pectinata (Schizaeaceae: Pteridophyta)

Bothalia ◽  
1994 ◽  
Vol 24 (2) ◽  
pp. 203-210 ◽  
Author(s):  
B. M. Parkinson
Keyword(s):  
South Africa ◽  
Geographical Range ◽  
Spore Size ◽  
Sporoderm Development ◽  
Plasmodial Tapetum ◽  
Taxonomic Importance ◽  
Parietal Tapetum ◽  
Schizaea Pectinata

Schizaea pectinata (L.) Sw. was collected from the extreme ends of its geographical range in South Africa for a study of sporangial development, sporogenesis and tapetal organisation. Differences were noted in the gross morphology , in sporangium size, spore size and in the patterning of the outer exospore from the two sites. Coiled structures were associated with the development of the inner perispore in spores collected from the Transvaal, whereas dense, heterogeneous bodies were associated with the formation of this layer in spores from the Cape. Differences were also noted in the organisation of the tapetum. A cellular, parietal tapetum and a plasmodial tapetum were present in the Cape material when the spores had developed the sculptured outer exospore. In sporangia from the Transvaal, however, only a plasmodial tapetum was present at the same stage of sporoderm development. A detailed study of S. pectinata throughout its distribution is required to determine the taxonomic importance of these findings.

Development of the sporangia and associated structures in Schizaea pectinata (Schizaeaceae : Pteridophyta)

1995 ◽  
Vol 73 (12) ◽  
pp. 1867-1877 ◽  
Author(s):  
Barbara M. Parkinson
Keyword(s):  
Key Words ◽  
Microscope Study ◽  
Light Microscope ◽  
Plasmodial Tapetum ◽  
Mother Cells ◽  
Parietal Tapetum ◽  
Schizaea Pectinata

A light microscope study of the initiation of the frond and sporangial development in Schizaea pectinata revealed that sporangia arose from single-celled initials in marginal positions on narrow, strap-shaped pinnae. The sporangia were displaced to a superficial position by marginal development of a false indusial (pseudoindusial) structure. Divisions of a single, central initial with four cutting faces produced the archesporial tissue and a two-layered tapetum that differentiated into a combination tapetum consisting of an outer, cellular parietal tapetum and an inner, plasmodial tapetum that was intimately associated with the archesporial tissue and later with the developing spores. Mature sporangia had an apical annulus consisting mainly of a single tier of cells that differentiated from the layer of cells forming the sporangium wall. Thirty-two spore mother cells were produced and if no abortion occurred, approximately 128 spores developed within each sporangium. Key words: Schizaea pectinata, sporangial ontogeny, parietal tapetum, plasmodial tapetum, combination tapetum.

scholarly journals The distribution of the dwarf succulent genus Conophytum N.E.Br. (Aizoaceae) in southern Africa

Bothalia ◽  
2016 ◽  
Vol 46 (1) ◽  
Author(s):  
Andrew J. Young ◽  
Philip G. Desmet
Keyword(s):  
Climate Change ◽  
South Africa ◽  
Southern Africa ◽  
Conservation Planning ◽  
Cape Floristic Region ◽  
Geographical Range ◽  
Western Cape ◽  
Succulent Karoo ◽  
Winter Rainfall ◽  
Rainfall Region

Background: The dwarf succulent genus Conophytum N.E.Br. is one of the most species rich in the Aizoceae. The genus is most closely associated with a region of high floral endemism and biodiversity, the Succulent Karoo biome in south-western Africa.Objectives: To examine the distribution of Conophytum in south-western Namibia and in the Northern and Western Cape Provinces of South Africa.Method: A database comprising 2798 locality records representing all known species and subspecies of the genus Conophytum has been constructed.Results: The genus is primarily restricted to the arid winter-rainfall region of the Northern and Western Cape Provinces of South Africa and south-western Namibia, within the Greater Cape Floristic Region. Whilst taxa are found across all the main biomes in the region (the Succulent Karoo, Nama Karoo, Desert and Fynbos biomes), 94% of Conophytum taxa are found only in the Succulent Karoo biome and predominantly (88% of taxa) within South Africa. Endemism within specific bioregions is a feature of the genus and ~60% of taxa are endemic to the Succulent Karoo. Approximately 28% of all taxa could be considered point endemics. Whilst the genus has a relatively wide geographical range, we identify a pronounced centre of endemism in the southern Richtersveld.Conclusion: The genus Conophytum can be used as a good botanical model for studying patterns of diversity and speciation in the Succulent Karoo biome, the effects of climate change on dwarf succulents, and for informing conservation planning efforts.

ANTHOCYANINS IN RIPE FRUIT OF THE SPARKLEBERRY, Vaccinium arboreum MARSH

1982 ◽  
Vol 62 (3) ◽  
pp. 683-687 ◽  
Author(s):  
W. E. BALLINGER ◽  
E. P. MANESS ◽  
J. R. BALLINGTON
Keyword(s):  
Geographical Range ◽  
Ripe Fruit ◽  
Taxonomic Importance ◽  
Vaccinium Arboreum

The extracted and purified anthocyanins (Acy) of Vaccinium arboreum Marsh [section Batodendron (Nutt.) Klotzch], commonly called the sparkleberry, were indentified as the 3-monoglycosides of the aglycones delphinidin, petunidin, malvidin, cyanidin, and peonidin with the sugars arabinose, galactose, and glucose (except for cyanidin and malvidin) (or 13 of a potential 15 Acy). Vaccinium arboreum fruit contains Acy which are extremely similar to those reported for the fruits of highbush and lowbush blueberries (subgenus Cyanococcus). Vaccinium arboreum has at least 12 Acy, while those of V. stamineum (subgenus Polycodium), whose geographical range is similar to that of V. arboreum, has only three (monoglycosides of the sugars galactose, arabinose, or glucose with the aglycone cyanidin). If Acy of fruits were to be considered of taxonomic importance, V. arboreum would appear to be more closely associated with subgenus Cyanococcus than with Polycodium which is associated with subgenus Oxycoccus.

Time and Latitude in South Africa

1972 ◽  
Vol 1 ◽  
pp. 27-38
Author(s):  
J. Hers
Keyword(s):  
South Africa ◽  
Cape Town ◽  
Astronomical Observations ◽  
Royal Observatory ◽  
The Republic ◽  
Astronomical Determination ◽  
Limited Accuracy ◽  
Better Than

In South Africa the modern outlook towards time may be said to have started in 1948. Both the two major observatories, The Royal Observatory in Cape Town and the Union Observatory (now known as the Republic Observatory) in Johannesburg had, of course, been involved in the astronomical determination of time almost from their inception, and the Johannesburg Observatory has been responsible for the official time of South Africa since 1908. However the pendulum clocks then in use could not be relied on to provide an accuracy better than about 1/10 second, which was of the same order as that of the astronomical observations. It is doubtful if much use was made of even this limited accuracy outside the two observatories, and although there may – occasionally have been a demand for more accurate time, it was certainly not voiced.

Combining Professional Interests and Travel: People to People Citizen Ambassador Program

2011 ◽  
Vol 1 (2) ◽  
pp. 47-54
Author(s):  
Alex Johnson ◽  
Amanda Hitchins
Keyword(s):  
South Africa ◽  
Health Education ◽  
Communication Disorders ◽  
Social Conditions ◽  
Speech Language Pathologists ◽  
Exchange Program

Abstract This article summarizes a series of trips sponsored by People to People, a professional exchange program. The trips described in this report were led by the first author of this article and include trips to South Africa, Russia, Vietnam and Cambodia, and Israel. Each of these trips included delegations of 25 to 50 speech-language pathologists and audiologists who participated in professional visits to learn of the health, education, and social conditions in each country. Additionally, opportunities to meet with communication disorders professionals, students, and persons with speech, language, or hearing disabilities were included. People to People, partnered with the American Speech-Language-Hearing Association (ASHA), provides a meaningful and interesting way to learn and travel with colleagues.

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