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If you’re afraid you’ve missed the boat on planting for the year just because the dog days of summer have set in, don’t worry. There are perennial flowers and herbs that will actually thrive with a late summer planting schedule. From blooms that will give your garden color throughout the fall to bulbs that do best when they’re in the ground for months before their spring season to herbs that will stay evergreen year-round, you have your pick of August-friendly perennials……..Continue reading….

By : Heather Bien

Source: Southern Living

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Critics:

The characteristic feature of angiosperms is the flower. Its function is to ensure fertilization of the ovule and development of fruit containing seeds. It may arise terminally on a shoot or from the axil of a leaf. The flower-bearing part of the plant is usually sharply distinguished from the leaf-bearing part, and forms a branch-system called an inflorescence.

Flowers produce two kinds of reproductive cells. Microspores, which divide to become pollen grains, are the male cells; they are borne in the stamens. The female cells, megaspores, divide to become the egg cell. They are contained in the ovule and enclosed in the carpel; one or more carpels form the pistil. The flower may consist only of these parts, as in wind-pollinated plants like the willow, where each flower comprises only a few stamens or two carpels.

In insect- or bird-pollinated plants, other structures protect the sporophylls and attract pollinators. The individual members of these surrounding structures are known as sepals and petals (or tepals in flowers such as Magnolia where sepals and petals are not distinguishable from each other). The outer series (calyx of sepals) is usually green and leaf-like, and functions to protect the rest of the flower, especially the bud.

The inner series (corolla of petals) is, in general, white or brightly colored, is more delicate in structure, and attracts pollinators by colour, scent, and nectar. Most flowers are hermaphroditic, producing both pollen and ovules in the same flower, but some use other devices to reduce self-fertilization. Heteromorphic flowers have carpels and stamens of differing lengths, so animal pollinators cannot easily transfer pollen between them.

Homomorphic flowers may use a biochemical self-incompatibility to discriminate between self and non-self pollen grains. Dioecious plants such as holly have male and female flowers on separate plants. Monoecious plants have separate male and female flowers on the same plant; these are often wind-pollinated, as in maize but include some insect-pollinated plants such as Cucurbita squashes.

Charles Darwin in his 1878 book The Effects of Cross and Self-Fertilization in the Vegetable Kingdom in the initial paragraph of chapter XII noted “The first and most important of the conclusions which may be drawn from the observations given in this volume, is that generally cross-fertilisation is beneficial and self-fertilisation often injurious, at least with the plants on which I experimented.” 

Flowers emerged in plant evolution as an adaptation for the promotion of cross-fertilisation (outcrossing), a process that allows the masking of deleterious mutations in the genome of progeny. The masking effect is known as genetic complementation. Meiosis in flowering plants provides a direct mechanism for repairing DNA through genetic recombination in reproductive tissues.

Sexual reproduction appears to be required for maintaining long-term genomic integrity and only infrequent combinations of extrinsic and intrinsic factors permit shifts to asexuality. Thus the two fundamental aspects of sexual reproduction in flowering plants, cross-fertilization (outcrossing) and meiosis appear to be maintained respectively by the advantages of genetic complementation and recombinational repair

Human impact on the environment has driven a range of species extinct and is threatening even more today. Multiple organizations such as IUCN and Royal Botanic Gardens, Kew suggest that around 40% of plant species are threatened with extinction. The majority are threatened by habitat loss, but activities such as logging of wild timber trees and collection of medicinal plants, or the introduction of non-native invasive species, also play a role.

Relatively few plant diversity assessments have considered climate change, yet it is starting to impact plants as well. About 3% of flowering plants are very likely to be driven extinct within a century at 2 °C (3.6 °F) of global warming, and 10% at 3.2 °C (5.8 °F). In worst-case scenarios, half of all tree species may be driven extinct by climate change over that timeframe. Conservation in this context is the attempt to prevent extinction, whether in situ by protecting plants and their habitats in the wild, or ex situ in seed banks or as living plants.

Some 3000 botanic gardens around the world maintain living plants, including over 40% of the species known to be threatened, as an “insurance policy against extinction in the wild.” The United Nations’ Global Strategy for Plant Conservation asserts that “without plants, there is no life”. It aims to “halt the continuing loss of plant diversity” throughout the world.

Review finds lack of evidence as to whether planting around our homes reduces the pollution we breathe  01:28