. Morphology of spermatophytes. [Part I. Gymnosperms]. Gymnosperms; Plant morphology. MORPHOLOGY OP SPBRMATOPHYTES publislied his great monograph of the group, and incidentally touched upon the stem anatomy of several genera. In 1861 Mettenius * published an account of Cycadean stems which has remained until recently the chief source of information about them. He included Cycas revoluta, Ence-plialartos horrida, Dioon edule, and Zamia muricata, finding in the last two genera none of the secondary cortical bundles characteristic of the first two. In 1885 Costantin and Morot ^^ published an acco
. Morphology of spermatophytes. [Part I. Gymnosperms]. Gymnosperms; Plant morphology. MORPHOLOGY OP SPBRMATOPHYTES publislied his great monograph of the group, and incidentally touched upon the stem anatomy of several genera. In 1861 Mettenius * published an account of Cycadean stems which has remained until recently the chief source of information about them. He included Cycas revoluta, Ence-plialartos horrida, Dioon edule, and Zamia muricata, finding in the last two genera none of the secondary cortical bundles characteristic of the first two. In 1885 Costantin and Morot ^^ published an account of the structure of the pericycle of Cycas Siamensis, claiming that in it the cortical cambium zones have their origin. In 1890 Solms-Laubach ^'' published an account of Stangeria paradoxa, in which the vascular bundles are traced from the peduncles to their juncture with the stem system, and no evidence of secondary cortical bundles is found. In 1891 Strasburger 18 brought together the knowledge of stem anat- omy with reference to Cycas, but did not in- clude other genera. The most important contribu- tions to the knowledge of stem anatomy since are those of Worsdell 21. 30 on Macrozamia and Bowenia, and that of Scott ^^ on the pedun- cles of Cycads. The structure common to all of the stems investigated is a large pith surrounded by a thick cylinder of open collateral bundles and broad pith rays, and a conspicuous cortical region. The primary bundles are common, and the primary cambium is either short-lived or somewhat persistent. In Zamia, Dioon, and Stangeria no further structures occur to interfere with the resemblance to an ordinary coniferous or dicotyledonous stem, and secondary thickening, whatever it may amount to, is effected by the primary cambium. A conspicuous feature of the structure of Cycas, Encephal-. FiG. 3. — Stangeria paradoxa, staminate plant; about one fifteenth natural size.—From Warm- ing-Potter's Handbook of Systematic Please note that
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