SUPPLEMENT 



food for growth of the young sporophyte ; so it is apparent that this 

 macrospore is analagous to an ovule, which also contains, besides 

 stored food, an egg cell surrounded by a tissue more or less similar to 

 archegonium and prothallium. The prothallium produced by the 

 microspore consists of but one cell, and bears but one antheridium 

 containing spermatazoids ; so the microspore approaches the pollen 

 grain in simplicity of structure, for there is one portion of the pollen 

 grain that is supposed to correspond to a spermatazoid. 



The ovules of the Coniferae are more nearly analagous to macro- 

 spores than are the ovules of higher spermaphytes, but a thorough 

 study of the fertilization of seed-bearing plants requires more skill 

 than a like study of lower plants ; so the old term Cryptogram, mean- 

 ing hidden fertilization, is really more applicable to higher than to 

 lower plants. On the other hand, the transference of the fertilizing 

 cell, that is pollination, is easily observed in seed-bearing plants, 

 while the corresponding process in lower plants always occurs in 

 water and can be seen only with the aid of the microscope. 



The lowest of Archegoniatae, the liverworts, vary in form. Some 

 of them are as thin and minute as fern prothallia, which they closely 

 resemble, while the higher ones, the scale-mosses, resemble mosses, 

 having slender stems and thin, green leaves ; those in the illustration 

 are of the type most common in California. No. 10, Fig. 30, the 

 Lunularia, is a common green-house pest; like many other plants 

 growing under very favorable conditions, this liverwort reproduces only 

 by fragments ; the fragments in this case are tiny green buds, called 

 gemmae ; they are contained in the crescents at the tip of the frond. 

 No. 9 is the female plant of a very common, native liverwort Fimbriaria 

 Californica. This liverwort is perennial ; like many other California 

 liverworts, it survives the dry season by giving up its moisture and 

 curling its upper surface inward until it seems a fossil, rather than a 

 dormant plant. With the first rains the plants expand at once, and 

 colonies of them, usually forming rosettes, are common and rather 

 conspicuous in springy, or moist, shady places. The plants of the 

 female colonies have at first a nearly smooth upper surface, then a 

 tiny ball appears, and they ultimately become like the one in the 

 picture ; the male plants have ridges on the upper surface. The 

 spores of Fimbriaria Californica are very interesting, and are easily 

 shown with low powers of the microscope. They do not mature until 

 the summer months, but in winter some can usually be found still 

 adhering to the old capsules. Shake out the coarse, yellow powder 

 on a dry slide, moisten very slightly by breathing on it, mount with- 

 out cover glass, and examine quickly. Besides the large, rough 



44 



