ILLUSTRATED FLORA. 



Subkingdom PTERIDOPHYTA.* 



FERNS AND FERN-ALLIES. 



Plants containing woody and vascular tissues in the stem and producing spores 

 asexually, which, on germination, develop small mostly flat green structures called 

 prothallia (gametophyte). On these are borne the sexual reproductive organs, 

 the female known as archegones, the male as antherids. From the fertilization 

 of the oosphere in the archegone by spermatozoids produced in the antherids, the 

 asexual phase (sporophyte) of the plants is developed; this phase is represented 

 by an ordinary fern, lycopod or horsetail. 



This subkingdom comprises about 6,000 living species, of which more than three-fourths 

 are confined to tropical regions. The number of extinct species known probably exceeds 

 those living. They appeared on the earth in the early part of the Palaeozoic Era, reached 

 great abundance in Carboniferous Time, but have since been mainly replaced by plants of 

 higher organization, so that at present they form only a small proportion of the total flora. 

 The time of year noted under the species indicates the season at which the spores are mature. 



Family 1. OPHIOGLOSSACEAE Presl, Tent. Pterid. 6. 1836. 



Adder's-tongue Family. 



Succulent plants consisting of a short fleshy rootstock bearing one or several 

 leaves and numerous fibrous often fleshy roots. Leaves erect or pendent, con- 

 sisting of a simple, palmately or dichotomously lobed, pinnately compound or 

 decompound, sessile or stalked, sterile blade, and one or several separate stalked 

 fertile spikes or panicles (sporophyls), borne on a common stalk. Sporanges 

 formed from the interior tissues, naked, each opening by a transverse slit. Spores 

 yellow, of one sort. Prothallia subterranean, usually devoid of chlorophyl and 

 associated with an endophytic mycorhiza. 



Five genera, the following well represented in both hemispheres ; the others tropical. 

 Veins reticulate; sporanges cohering in a distichous spike. 1. Ophioglossum. 



Veins free ; sporanges distinct, borne in spikes or panicles. 2. Botrychium. 



i. OPHIOGLOSSUM [Tourn.] L. Sp. PL 1062. 1753. 



Small terrestrial plants, with small, erect, fleshy, often tuberous, rootstocks bearing 

 fibrous naked roots and 1-6 slender, erect leaves, these consisting usually of a short, cylindric 

 common stalk, bearing at its summit a simple entire lanceolate to reniform sessile or short- 

 stalked sterile blade with freely anastomosing veins and usually a single simple long-stalked 

 spike, the sporophyl, formed of 2 rows of large coalescent sporanges ; spores copious, sulphur 

 yellow. Bud for the following season borne at the apex of the rootstock, exposed, distinct 

 and free from the leaf of the present season. [Name from the Greek, signifying the tongue 

 of a snake, in allusion to the form of the narrow spike.] 



About 45 species of wide geographic distribution. Besides the following 4 others occur in the 

 southern and western United States and Alaska. Type species : Ophioglossum vulgatum L. 

 Leaves usually solitary ; sterile blade obtuse or acutish, never apiculate. 1. O. vulgatum. 



Leaves often in pairs ; sterile blade acutish or apiculate. 



Sterile blade elliptic, rarely ovate, apiculate ; areoles broad. 2. 0. Engelmanni. 



Sterile blade lanceolate, acutish, somewhat apiculate ; areoles narrow. 3. O. arenarium. 



*Text (except Equisetaceae and Isoetaceae) revised by William R. Maxon. 



