3 To find out what development takes place in the early formation of a seed, 

 compare the ovaries of some pea blossoms, some partially developed pods, and 

 some mature pods of peas. Identify the ovules in the ovary of the blossom; com- 

 pare them with the ovules in a later stage and with the ripe seeds. Find evidences 

 that not all the ovules in the pea pods were fertilized. Describe the development 

 that takes place after fertilization. 



4 To discover structures that favor or hinder self-pollenation or that favor 

 cross-poUenation by wind or by insects, examine as many diflerent varieties of 

 flowers as are to be had and note: 



u. Position of stamens with relation to floral envelope (whether exposed to the 

 wind or shielded; whether corolla permits the pollen to be dusted off on any casual 

 contacts, or is arranged so as to permit insects to enter only along special paths). 



b. Position of the anthers in relation to the stigma (whether above or on a 

 lower level, whether on same or on separate flowers). 



c. Relative time of ripening of stigma and pollen (whether at the same time 

 on a given flower, or whether at different times on the same flower). 



d. The character and amount of pollen produced. 



e. Shape and position of pistil with reference to contact with visiting insects or 

 with wind-blown pollen. 



/. Presence or absence of distinct colors, odor or sweet nectar. 



List the structures that favor self-pollenation; those that hinder it; those that 

 favor insect pollenation; those that favor wind pollenation. List the flowers 

 showing each of these adaptive structures. 



5 To discover how seeds travel, collect as many kinds of seeds as are available 

 in an open meadow or vacant lot in the fall of the year. Note the various struc- 

 tures that relate seeds to moving air, animals, or other agencies. Look for seeds or 

 fruits with hooks or spines; with a pappus, a hairy parachutelike arrangement; 

 with wings. Look for fruits or pods which, as they ripen and dry, mechanically 

 throw the seeds; for fruits encased in fleshy pulp. Note any other ways in which 

 seeds travel. Classify the various kinds of seeds according to the manner or agency 

 of dispersal. 



6 To find the relation of the parts of the seed to the parts of the young 

 plant, soak seeds of several varieties overnight (use Lima beans, peas, and corn 

 grains). Remove coat from soaked seeds and carefully lay apart structures found. 

 Make drawings to show structures and their attachments to one another. Identify 

 the following: the hilum, the scar of attachment of the seed inside the fruit; the 

 micropylc, the tiny hole through which the pollen-tube passed into the ovule; the 

 embryo, or young plant, usually the entire contents of the seed coat; the cotyle- 

 dons, or seed leaves, the large fleshy structures in such seeds as beans, peas, etc.; 

 the hypocotyl, the little "tail" to which both cotyledons are attached; and the 

 epicotyl, or plumule, usually lying between the cotyledons and attached to both. 

 Compare the parts of embryo in different species. 



7 To see how varying amounts of nutrition affect the growth of seedlings, 

 place a quantity of soaked bean seeds and corn grains in a germinating dish, be- 

 tween layers of wet blotting paper; cover and set in a warm place. When the seeds 



415 



