. La botanique pour les académies et collèges : composé de développement de la plante et la structure d'algues de clématites. Botanique ; 1889. Le développement des végétaux. 25 pour faire du pain de^ durent plus longtemps, est également composé de ces fossiles ; pour alors que la coquille est à fusil, la cellule elle-même est riche en amidon, qui a été préservé grâce à d'innombrables siècles. 44. La reproduction, la conjugaison,double âWe ici voir Reproduction double, ou la reproduction (naissance à partir de deux personnes). À l'échéance de la mère à la cellule se divise en deux parties égales, appelées valves. Chaque valve est un particulier (Fig. 13, B), mais il est incapable de se reproduire par

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. Botany for academies and colleges: consisting of plant development and structure from seaweed to clematis. Botany; 1889. PLANT DEVELOPMENT. 25 to make tlie loaf last longer, is also composed of these fossils; for whilst the shell is flinty, the cell itself is rich in starch, which has been preserved through countless ages. 44. Dual Reproduction, Conjugation, âWe here see Dual Reproduction, or Paired reproduction (birth from two individuals). At maturity the mother-cell divides into two equal parts, called valves. Each valve is an individual (Fig. 13, B), but it is incapable of reproduction by itself alone. Presently two valves approach each other (Fig. 13, C); their walls in the central part unite and then rupture, so that their contents mingle in one mass; this mass de- velops a wall of cellulose (Fig. 13, D), and becomes a spore called a Zygospore, or Jointspore (Gr. Zygob, I join). Then the valves die, and the Zygospore becomes a complete individual, rupturing into two valves like the parent. The two valves thus produced are not apt to rejoin; each seeks a stranger; thus showing that Nature, even in her lowest types, teaches the advantage of cross-fertilization. This mode is the first hint or prophecy of two sexes; but here, though the cells are separate, they are exactly alike, and both are active. This mode is therefore called Conjugation, or Joining. 45. Green Seaweeds. âWe next find a plant which takes the form of a branch, and fastens it- self to the earth or stone by projections which serve the purpose of hold-fasts, and sinmlate roots; but they are not true roots, for they have no power of ab- sorption. This branch- ing plant consists of a single cell, like a glove with many fingers. The ^"'- ''â ^â âBryopmpiumosa, nat. size. Vaucheria (Fig. 1) is an example; the lovely little Bry- opsis (Fig. 15) is another. B 3. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - colorati

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