Fig. 246.—Section of an Apple.
Fig. 247.—Cross-section of an Apple.
Gymnospermous Fruits.—In pine, spruces, and their kin, there is no fruit in the sense in which the word is used in the preceding pages, because there is no ovary. The ovules are naked or uncovered, in the axils of the scales of the young cone, and they have neither style nor stigma. The pollen falls directly on the mouth of the ovule. The ovule ripens into a seed, which is usually winged. Because the ovule is not borne in a sac or ovary, these plants are called gymnosperms (Greek for “naked seeds”). All the true cone-bearing plants are of this class; also certain other plants, as red cedar, juniper, yew. The plants are monœcious or sometimes diœcious. The staminate flowers are mere naked stamens borne beneath scales, in small yellow catkins which soon fall. The pistillate flowers are naked ovules beneath scales on cones that persist (Fig. [29]). Gymnospermous seeds may have several cotyledons.
Suggestions.—168. Study the following fruits, or any five fruits chosen by the teacher, and answer the questions for each: Apple, peach, bean, tomato, pumpkin. What is its form? Locate the scar left by the stem. By what kind of stem was it attached? Are there any remains of the blossom at the blossom end? Describe texture and colour of surface. Divide the fruit into the seed vessel and the surrounding part. Has the fruit any pulp or flesh? Is it within or without the seed vessel? Is the seed vessel simple or sub-divided? What is the number of seeds? Are the seeds free, attached to the wall of the vessel, or to a support in the centre? Are they arranged in any order? What kind of wall has the seed vessel? What is the difference between a peach stone and a peach seed? 169. The nut fruits are always available for study. Note the points suggested above. Determine what the meat or edible part represents, whether cotyledons or not. Figure 248 is suggestive. 170. Mention all the fleshy fruits you know, tell where they come from, and refer them to their proper groups. 171. What kinds of fruit can you buy in the market, and to what groups or classes do they belong? Of which fruits are the seeds only, and not the pericarps, eaten? 172. An ear of corn is always available for study. What is it—a fruit or a collection of fruits? How are the grains arranged on the cob? How many rows do you count on each of several ears? Are all the rows on an ear equally close together? Do you find an ear with an odd number of rows? How do the parts of the husk overlap? Does the husk serve as protection from rain? Can birds pick out the grains? How do insect enemies enter the ear? How and when do weevils lay eggs on corn? 173. Study a grain of corn. Is it a seed? Describe the shape of a grain. Colour. Size. Does its surface show any projections or depressions? Is the seed-coat thin or thick? Transparent or opaque? Locate the hilum. Where is the silk scar? What is the silk? Sketch the grain from the two points of view that show it best. Where is the embryo? Does the grain have endosperm? What is dent corn? Flint corn? How many kinds of corn do you know? For what are they used?
Fig. 248.—Pecan Fruit.
Note to Teacher.—There are few more interesting subjects to beginning pupils than fruits,—the pods of many kinds, forms, and colours, the berries, and nuts. This interest may well be utilized to make the teaching alive. All common edible fruits of orchard and vegetable garden should be brought into this discussion. Of dry fruits, as pods, burs, nuts, collections may be made for the school museum. Fully mature fruits are best for study, particularly if it is desired to see dehiscence. For comparison, pistils and partially grown fruits should be had at the same time. If the fruits are not ripe enough to dehisce, they may be placed in the sun to dry. In the school it is well to have a collection of fruits for study. The specimens may be kept in glass jars. Always note exterior of fruit and its parts; interior of fruit with arrangement and attachment of contents.