SEXUAL SPORES. Only two names. zygospores and zygotes, are used to designate sexual spores which result from the anion of similar gametes (fig. 5, 7). (See SOGAM Y. ) 06spores, duced by all but the lowest plants, are formed by the union of dissimilar gametes (see HETERO GAMY ) known as sperms and eggs (otispheres). See SEx in plants.
Under suitable conditions any spore begins to form a new plant, the process being called germi nation. In some cases the germination is imme diate; in others it is delayed for a longer or shorter period by unfavorable conditions, as in winter. Spores adapted to delayed germination are called resting spores, and may be recognized by their unusually heavy protecting wall. See LEPRODUCTI0\.
The methods of spore dispersal are as diverse as the various means of seed dispersal. In ninny of the lower forms, as in the algae and sonic fungi, zoiispores may distribute the species over wide areas. Most aerial spores are light and usually small, and are thus readily scattered great dis tances by wind, a fact evidenced by the usually early appearance of ferns on new tropical is lands. _Mechanical expulsion and special devices
far separating or entangling spores, as the ela tees of Equisetum (fig. 3), are common.
SPoRER, spe'rer, GUSTAV FRIEDRIUIT WIL HELM ( 1S22-93). A German astronomer. born in Berlin and educated there. He taught at Bromberg, at Prenzlau, and at Anklam (since 1S49). Here he began in 1860 to observe sun spots with the view of determining the law of solar rotation. Through a Government endow ment a solar observatory was erected by him at Anklam. Sperer arrived independently at a con clusion similar to that of Carrington concerning the equatorial quickening of the sun's movement on its axis. In 1868 he took part in an expedition to East India for observing a total eclipse of the sun. The structure of the chromo sphere was also investigated by SpOrer. This showed the chromosphere to be of the same na ture as the vast protrusions from it. From 1874 to 1S94 Spbrer was observer at the astrophysical observatory at Potsdam.