In driving or walking along the country roads, we may find ourselves suddenly immersed in a wave of delightful fragrance, and if we look for the source we may find this friendly plant flourishing in the most forbidding of soils. Growing as a weed, it brings sweet perfume to us, and at the same time nitrogen, aeration and drainage to the hopeless soil, making rich those places where other weeds have not the temerity to attempt to grow. When the soil is generous, the sweet clover often grows very tall, sometimes as high as ten feet. It is a cheerful, adaptable and beneficial plant, and I never see it without giving it a welcome, which, I am sorry to say, I cannot always grant to other roadside wayfarers. The sweet clovers are European. _The White Sweet Clover (M. alba)_ is sometimes called Bokhara clover and has white flowers (Fig. 249). _The Yellow Sweet Clover (M. officinalis)_ has yellow blossoms. It has interesting old English names, such as Balsam Flowers, King's Clover and Heartwort. [Illustration: _Fig. 249. White sweet clover._] QUESTIONS ON THE CLOVERS. _Two general kinds of types of studies are to be made of the clovers: identification studies, whereby you will come to know the kinds of clover; life history studies, whereby you will come to know under what conditions the plants live and thrive. The latter is the more important, but the former usually precedes it, for one is better able to discover and discuss the biological questions when he is acquainted with the species. The following questions will bring out some of the important biological aspects:_ 1. How many of the true clovers, the medics, and the sweet clovers do you know? 2. Send me properly labelled pressed specimens of the leaves and blossoms of the clovers that you have been able to find. 3. Dig a root of red clover and find the nodules on it. Please describe them. 4. What methods does the U. S. Department of Agriculture employ to inoculate the soil with bacteria so that alfalfa may grow? 5. How do clover roots protect the land from the effects of heavy rains? 6. How do the clover plants conserve the moisture in the soil? 7. How does this conservation of moisture aid the farmer and orchardist? 8. What is a cover-crop, and what are its uses? 9. Why do farmers sow red clover with grass seed? 10. How do the habits of the stems of white clover differ from those of other clovers? 11. Why is white clover so desirable for lawns? 12. Compare the floweret of the red clover with the sweet pea blossom and describe the resemblance. 13. Study a head of white clover from the time it opens until it is brown, and tell what changes take place in it day by day. 14. What has happened to the flowerets that are bent downward around the stalk? 15. Watch one of these flowerets deflect, and describe the process. 16. How many flowerets do you find in a head of red clover? Of white clover? Of alsike? 17. Which flowerets open first in a head of red clover?