When some plants have the male and female reproductive organs in separate flowers on separate plants, they are __________.

Night Flowering Plants

Evening Primrose

These soft-scented flowers have four satiny heart-shaped petals that come together forming 2 inch open cups with frilly long stamens. When they open in the evening, the blossoms are a soft clear white that gradually fades into pink.

Moonflowers

These 6 inch trumpet flowers unfurl in slow motion every night just at sunset. Pure white with faint green tracings, the blossoms are very fragrant all evening. By noon, the flowers dwindle and close and are barely seen in the dense foliage.

Angel's Trumpet

Datura meteloides has six-inch white trumpet flowers that open at night and remain open well into the following day. This flower is a favorite subject of Georgia O'Keefe. Warning: poisonous. Don't eat it to get a high.

Nottingham Catchfly, Night-flowering Catchfly, and White Champion These are all members of the genus Silence, which also has several day-blooming members. These plants have sticky stems, hence the name "catchfly".

Which of the following night flowering plants open slowly every night just at sunset?

A．Evening Primrose.

B．Moonflowers.

C．Angel's Trumpet.

D．Nottingham Catchfly, Night-flowering Catchfly, and White Champion.

Seed catalogues feature hundreds of flowering species. For the persons just beginning garden this can be bewildering, and below are the details of some popular choices, nearly all of which should be sown in the spring. With the exception of busy lizzies, which need a little care, they are all very easy to grow from seed. Dahlias These are sturdy plants bearing showy flowers in a wide range of rather gaudy colors. Sow in a frame in April and plant the seedlings out when frosts are over. Dahlias flower throughout the summer and into the autumn. When autumn frosts begin to make them look unhappy, you should dig up the tuberous roots and save them. A frost-free loft, shed or garage is the ideal place. The following spring you plant the tubers instead of sowing seed again. Lupins Lupins are hardy perennials. This means that the plants will stay in your garden and carry on flowering year after year. Seed sown in April will usually give you some spikes of colors in the first summer, and year by year the plants get bigger and the flowering stems get taller and grander. Selective breeding has led to the introduction of some fine, bicolored varieties in some dazzling shades. The short-lived flowers make a real misunderstanding spectacle. Busy lizzies Like dahlias, busy lizzies need to be started off under glass, as they cannot stand frost, and panting out is best done in May. Outdoor flowering ends in September, so beat the frosts and bring your favorite specimens indoors to give your home some sinter color! Indoors they will carry on flowering indefinitely, though you may like to plant them out again when spring returns. Like pansies (below) they do very well in sun or shade, but the soil must be moist. Most varieties grow to be a height of only 20 cm or so. Potentillas Potentillas are hardy shrubs. In other words, the woody branches spring from ground level—there is no central trunk. Seed is probably best sown in autumn, in which case you should keep the plants in a sheltered spot until April offers favorable conditions for planting out. Once flowering begins in early summer the best varieties (such as Melton Fire) will stay in bloom almost ceaselessly for years on end while at the same time spreading out to provide ground cover or a low hedge. Pansies Pansies have a good long flowering season year after year, and some varieties can be sown in spring to give truly splendid results the first autumn. Unlike dahlias and lupins, which can easily grow a meter tall, pansies grow no higher than 10 or 20 cm. Their soil, position and moisture requirements are just like those of busy lizzies but pansies differ in being hardy. Give them a try! Questions 1-3 Decide whether the following statements are true (T) or false (F) according to the passage. 1. Both dahlias and lupins, which are sown in April, need protecting from frost. 2. Brought indoors in autumn, dahlias, busy lizzies and potentillas will carry on flowering almost non-stop. 3. Among all the flowers busy lizzies are not very easy to grow from seed.

There are some ______ (art) flowers on the table.

Biological Clock When the sun rises on a warm and sunny day, you can see some flowers open up. When they close late in the afternoon, other flowers open. Biological rhythms（生物节律）, like the opening and closing of flowers, happen all over nature. But not all of them are daily rhythms. Some, like the beating of our heart, happen every second.______（26） Scientists use the term biological clock to describe the timing that controls biological rhythms.______（27）In some animals it is probably controlled by the brain. In plants and other living things that have no brain, it must be something else. The migration of animals happens when a signal sent out. For example, when days become shorter, birds leave the northern parts of the world and fly south where it is warm.______（28） Humans also have biological clocks that control their daily rhythms. When people travel by plane from one continent to another, they often cross many time zones. Their internal clocks don’t seem to work correctly. We call this jet lag（时差）.______（29）People who work night shifts also have problems with their biological clocks. They may not be as active as people who work during the daytime. Biological clocks control many rhythms of life.______（30）Doctors are looking for new ways to make travelling more comfortable and medical treatment more effective. ______.A.But where can you find it?

B.This makes them feel tired.

C.In the summer they fly back to have babies.

D.We are learning more and more about them.

E.Biological clocks can be adjusted.

F.Other rhythms are based on months, seasons or years.

______.A.But where can you find it?

B.This makes them feel tired.

C.In the summer they fly back to have babies.

D.We are learning more and more about them.

E.Biological clocks can be adjusted.

F.Other rhythms are based on months, seasons or years.

______.A.But where can you find it?

B.This makes them feel tired.

C.In the summer they fly back to have babies.

D.We are learning more and more about them.

E.Biological clocks can be adjusted.

F.Other rhythms are based on months, seasons or years.

______.A.But where can you find it?

B.This makes them feel tired.

C.In the summer they fly back to have babies.

D.We are learning more and more about them.

E.Biological clocks can be adjusted.

F.Other rhythms are based on months, seasons or years.

______.A.But where can you find it?

B.This makes them feel tired.

C.In the summer they fly back to have babies.

D.We are learning more and more about them.

E.Biological clocks can be adjusted.

F.Other rhythms are based on months, seasons or years.

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