Elementary botany . elementarybotany00atki Year: 1898 FURTHER STUDIES ON GYMNOSPERMS. 215 developed entirely inside of the macrosporangium, and derives the nutriment for its growth from the cycas plant, which is the Fig. 279. Macrosporangium ot Cycas revoluta Fig. 280. Roentgen photograph of same, show- ing female prothallium. sporophyte. Archegonia are developed in this internal mass of cells. This aids us in deter- mining that it is the prothal- lium. In cycas it is also called endosperm, just as in the pines. 430. If we cut open one of the mature ovules, we can see the en- dosperm (prot

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Elementary botany . elementarybotany00atki Year: 1898 FURTHER STUDIES ON GYMNOSPERMS. 215 developed entirely inside of the macrosporangium, and derives the nutriment for its growth from the cycas plant, which is the Fig. 279. Macrosporangium ot Cycas revoluta Fig. 280. Roentgen photograph of same, show- ing female prothallium. sporophyte. Archegonia are developed in this internal mass of cells. This aids us in deter- mining that it is the prothal- lium. In cycas it is also called endosperm, just as in the pines. 430. If we cut open one of the mature ovules, we can see the en- dosperm (prothallium) as a whitish mass of tissue. Immediately sur- rounding it at maturity is a thin, papery tissue, the remains of the nucellus (macrosporangium), and outside of this are the coats of the ovule, an outer fleshy one and an inner stony one. 431. Microspores, or pollen, of cycas.—The cycas plant illustrated in the frontispiece is a female plant. Male plants also exist which have