180 



PHYLUM TRACHEOPHYTA: 



Figure 11.14 Life cycle of a fern; an., male sex organ; or., femole 

 sex organ; e., egg; g.s., germinating spore; s., sperm; z., zygote. {Used 

 by permission, from Arthur Cronquist, Introductory Botany, fforper, New 

 York, 1961.) 



pound, generally only one present; fertile leaves of 

 two parts, a lower sterile, or vegetative, leafy segment 

 and an upper, sporangia-bearing segment or spike 

 ("adder's tongue"); leaf not unrolling witfi growth, 

 petiole with clasping stipules; one spore type, gameto- 

 phyte bisexual, inconspicuous, underground, without 

 chlorophyll, and worm-like, its nutrition involving a 

 fungus relationship (Figure 11.15). 



Occurrence: three genera in a single family, Ophio- 

 glossaceae; one species of f/rlminlhuslachys in the Indo- 

 Malayan region; about 28 species of (Jphioglosstim 

 (adders-tongue ferns) and about 23 species of Botry- 

 chium (grape ferns) of world-wide distribution; all 

 small to average sized perennial herbs, some ever- 

 green, mostly of moist tropical and temjieratc forests; 

 fossils unknown. 



ORDER MARATTIALES (Tropical Ferns) 



Diai^niisis: known Irom Fennsylvanian to Recent; 

 about 14.S living, [jercnnial herbs to tree-like forms 

 ol the tropics, mostly forest plants that c losely resem- 

 ble the Filicales in i^ross appearance but have many 



Ophioglossales characters; stems reduced to rhizomes 

 or erect tuberous trunks; leaves large and pinnate, 

 sometimes simple but mostly compound or decom- 

 pound; some leaves resemble those of cycads; leaves 

 have clasping stipules and unroll with growth; spo- 

 rangia either are free but grouped (into sori), or are 

 fused (see psilopsids); sporangia on upper surface of 

 leaves; one kind of spore; gametophyte bisexual, con- 

 spicuous (mostly over 1 inch long), chlorophyllous, 

 flat, and ribbon- or heart-shaped (Figure 11.16). 



Figure 11.15 A grape fern, Bofrychmm (left), and an adder's tongue 

 fern, Ophiog/ossum (right). (Used by permission, from Comparative 

 Morphology of Vascular Plants by Adriance 5. Foster and Ernest M. 

 Gifford, Jr. San Francisco: W. H. Freeman and Co., 1959.) 



