The reproductive biology of Stellaria longipes Goldie (Caryophyllaceae) in North America

Flora ◽  
2007 ◽  
Vol 202 (5) ◽  
pp. 403-407 ◽  
Author(s):  
Thi Thu Thuy Dang ◽  
C.C. Chinnappa
Keyword(s):  
North America ◽  
Reproductive Biology ◽  
Stellaria Longipes

The biology of Canadian weeds. 119. Cannabis sativa L.

2003 ◽  
Vol 83 (1) ◽  
pp. 217-237 ◽  
Author(s):  
E. Small ◽  
T. Pocock ◽  
P. B. Cavers
Keyword(s):  
Law Enforcement ◽  
North America ◽  
Great Lakes ◽  
Key Words ◽  
Reproductive Biology ◽  
Cannabis Sativa ◽  
Biological Properties ◽  
Textile Fibre ◽  
Habitat Conditions ◽  
A Minor

Cannabis sativa has been cultivated for millennia in Eurasia and for centuries in North America, as a source of a textile fibre, oilseed, and intoxicating drugs such as marijuana. Considerable literature is available on the agricultural and biological properties of these basic three cultigens, but relatively little is published on wild-growing plants of the species. Most weedy C. sativa differ from the cultigens in a number of ecological properties, particularly with regard to reproductive biology. The species is the classical example of a “camp follower” that is exceptionally adapted to the habitat conditions around settlements: rich, highly manured, moist soils, and open areas resulting from recent removal or disturbance of the vegetation. In Canada, spontaneous populations have been found in all provinces, but forms that have re-evolved wild adaptations are concentrated along the St. Lawrence and lower Great Lakes. The ruderal plants pose a minor weed problem to agriculture but a major problem to law enforcement, and decades of eradication have exterminated many of the naturalized populations in Canada. With the recent re-authorization of hemp cultivation in Canada, it is inevitable that there will be additional escapes and a reinvigoration of the ruderal phase of the species. Mechanical eradication for 2 or 3 yr is effective at destroying populations, and young plants are easily eliminated by herbicide applications. Key words: Cannabis sativa, hemp, marijuana, marihuana, weed, oilseed

scholarly journals Reproductive biology of leafy spurge (Euphorbia esula L.): breeding system analysis

2000 ◽  
Vol 77 (11) ◽  
pp. 1684-1688
Author(s):  
Sarena M Selbo ◽  
Jeffrey S Carmichael
Keyword(s):  
North America ◽  
Reproductive Biology ◽  
Breeding System ◽  
Microscopic Examination ◽  
Reproductive Strategies ◽  
System Analysis ◽  
Leafy Spurge ◽  
Euphorbia Esula ◽  
Invasive Weed ◽  
Native Invasive

Leafy spurge (Euphorbia esula L.) represents a non-native, invasive weed that dominates many regions across North America. While many research efforts are aimed at controlling the growth and spread of this plant, relatively little is known about its breeding system. This study provides evidence that leafy spurge is self-compatible, with selfed plants producing roughly half as many seeds as outcrossed plants. Unpollinated flowers failed to set seed and thus preliminary tests for apomixis were negative. However, microscopic examination of pollinated flowers revealed that pollen tubes did not appear to enter ovules in either selfed or outcrossed flowers. Therefore, leafy spurge exhibits structural evidence that suggests pseudogamy may play a role in the reproductive strategies of this invasive weed.

scholarly journals The Reproductive Biology of the Softshell Clam,Mya arenaria, in Ireland, and the Possible Impacts of Climate Variability

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
M. E. Cross ◽  
S. Lynch ◽  
A. Whitaker ◽  
R. M. O'Riordan ◽  
S. C. Culloty
Keyword(s):  
North America ◽  
Climate Variability ◽  
Histological Examination ◽  
Reproductive Biology ◽  
Mya Arenaria ◽  
Eastern North America ◽  
Fertilisation Success ◽  
Male Ratio ◽  
The Mean ◽  
Softshell Clam

Little is known about the biology of the softshell clam in Europe, despite it being identified as a potential species to culture for food in the future. Monthly samples of the softshell clam,Mya arenaria, were collected intertidally from Co. Wexford, Ireland, over a period of sixteen months. The mean weight of sampled individuals was74±4.9 g and mean length was8.2±0.2 cm. Histological examination revealed a female-to-male ratio of 1 : 1.15. In 2010,M. arenariaat this site matured over the summer months, with both sexes either ripe or spawning by August. A single spawning event was recorded in 2010, completed by November. Two unusually cold winters, followed by a warmer-than-average spring, appear to have affectedM. arenariagametogenesis in this area, potentially affecting the time of spawning, fertilisation success, and recruitment of this species. No hermaphrodites were observed in the samples collected, nor were any pathogens observed. Timing of development and spawning is compared with the coasts of eastern North America and with other European coasts.

Fine structure and possible functions of the hermaphrodite duct of some pulmonate snails (Mollusca: Gastropoda)

1990 ◽  
Vol 48 (3) ◽  
pp. 68-69
Author(s):  
Alan N. Hodgson
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fine Structure ◽  
Seminal Vesicle ◽  
Reproductive Biology ◽  
Light Microscope ◽  
Light Microscope Level ◽  
Transmission Electron ◽  
Standard Techniques

The hermaphrodite duct of pulmonate snails connects the ovotestis to the fertilization pouch. The duct is typically divided into three zones; aproximal duct which leaves the ovotestis, the middle duct (seminal vesicle) and the distal ovotestis duct. The seminal vesicle forms the major portion of the duct and is thought to store sperm prior to copulation. In addition the duct may also play a role in sperm maturation and degredation. Although the structure of the seminal vesicle has been described for a number of snails at the light microscope level there appear to be only two descriptions of the ultrastructure of this tissue. Clearly if the role of the hermaphrodite duct in the reproductive biology of pulmonatesis to be understood, knowledge of its fine structure is required.Hermaphrodite ducts, both containing and lacking sperm, of species of the terrestrial pulmonate genera Sphincterochila, Levantina, and Helix and the marine pulmonate genus Siphonaria were prepared for transmission electron microscopy by standard techniques.

Sign in / Sign up

Export Citation Format

Share Document