. Physiological botany; I. Outlines of the histology of phænogamous plants. II. Vegetable physiology. Plant physiology; Plant anatomy. 440 113G. It was formerh- thought that no clear gradations could be detected between the"^ flowering plants and .the higher groups (3) Oophytes. In this group a mass of protoplasm, known as an oosphere, is fertilized by specialized threads or slender masses of protoplasmic matter termed antherozoids, coming from another part of the same or of another plant. By contact with these an- therozoids the oosphere he- comes an oospore, the start- in
. Physiological botany; I. Outlines of the histology of phænogamous plants. II. Vegetable physiology. Plant physiology; Plant anatomy. 440 113G. It was formerh- thought that no clear gradations could be detected between the"^ flowering plants and .the higher groups (3) Oophytes. In this group a mass of protoplasm, known as an oosphere, is fertilized by specialized threads or slender masses of protoplasmic matter termed antherozoids, coming from another part of the same or of another plant. By contact with these an- therozoids the oosphere he- comes an oospore, the start- ing-point of a newindividuah In this group, of which Fucus or rock-weed may he taken as an example, the fertilization is direct. In the examination of this group the student may em- ploy the common rock-weed which carpets the boulders along tlie coast. Sections should be made in the un- even pustulated part of the frond, aud in a vertical di- rection. Good preparations can be obtained from mate- rial which has been dried or from that which has been kept in alcohol, and winter specimens will be found especially good. Some of the species are dioicious, having the male elements in the conceptacles » /It^fisH '^ on one plant and the female elements in those upon an- other. (4) Carpophytes. The simplest plants of this het- erogeneous group are illus- trated by Fig. 211. The oosphere is contained in a specialized organ (the car- pogonium), which is fre- quently prolonged to form a style-like process (the tri- cKogyne). The antherozoids ^1^ are carried by water to this process, and fertilization results; the product of Fig. 210. Fucua, illustrating the fertilization of an oophyte. a, section throngli a conceptaclo exhibiting the reproductive organs; b anil c, the obspheres in different stages of development; d, antheridia with a single antherozoid ((/); e, an oSsphere surrounded by antherozoids; ./•, an oosphere gei-niinaling. (Thuret ) FjG. 211. Nemalion. , a carpophyte. I.,
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