GENUS TRILETES 



27 



tonic and Kremp (1955) interpret as borne 

 by some arborescent lycopods (Lepidoden- 

 draceae), they also may be related to the 

 arborescent lycopods. Their alliance within 

 the section Lagenicula is still in question 

 because we have no information from cone 

 studies as to their botanical affinity. 



Occurrence. — Spores of this species were 

 found in the coal in the Bethel (Moore- 

 town) Formation (maceration 943), Hardin 

 County, Kentucky. 



Triletes splendidus (Zerndt) Schopf, 

 Wilson, and Ben tall, 1944 



Plate 5, figure 8 



1937 Lagenicula splendida Zerndt (1937a), p. 13- 



14; pi. 18, figs. 1-4; pi. 19, figs. 1-5; pi. 20, 



figs. 1-4. 

 1944 Triletes splendida (Zerndt) Schopf, Wilson, 



and Bentall, p. 25. 

 1946 Triletes splendidus (Zerndt) Dijkstra, p. 50; 



pi. 16, figs. 173-175. 

 1955 Lagenicula splendida Zerndt, in Potonie and 



Kremp, p. 119. 



Description. — Megaspores originally more 

 or less spherical, having no preferred com- 

 pressional orientation, 1200 to 1540 ^ in 

 equatorial diameter (four complete speci- 

 mens, dry mounts). Apical prominence ex- 

 panded-pyramidal in shape, commonly 

 slightly constricted basally, 205 to 275 ^ 

 high and 255 to 340 /x wide. Trilete rays 

 distinct, up to 137 ^ in height including 

 spore coat thickness, less distinct on apical 

 prominence. Contact areas occupying a lit- 

 tle over three-fourths the proximal hemi- 

 sphere, some of them ornamented with 

 small acuminate tubercles. Arcuate ridges 

 not distinct, marked by the inception of ro- 

 bust distal ornamentation. Distal tubercles 

 35 to 70 fi long, 35 to 70 ^ in diameter at 

 their large hemispherical bases. Outwards 

 from the expanded bases, processes more 

 slender, usually acuminate at tip. Spore 

 coat 35 [x thick (one specimen measured). 



Discussion. — One very small individual 

 found among the above specimens is 755 ^ 

 in diameter, rounded triangular in outline, 

 possesses prominent rays and an apical 

 prominence 1 70 /jL in diameter. The distal 

 surface is covered with spines about 25 fx 



long and 25 ^ in diameter basally. Its small 

 size and pronounced subtriangular shape 

 distinguish it from the larger megaspores 

 of Triletes splendidus. Probably this spore 

 represents an immature spore of the species 

 comparable with those mentioned by Dijk- 

 stra (1957). 



These megaspores correspond closely to 

 those originally described by Zerndt (1937a, 

 p. 13-14) from the lower part of the 

 "couches marginales" (Dinantian?, Namu- 

 rian A of Poland) and to the specimen illus- 

 trated by Dijkstra (1952c, pi. 7, fig. 5), but 

 have smaller tubercles than those from Scot- 

 land described earlier by Dijkstra (1946, p. 

 50). Dijkstra (1957) reports these spores 

 as common throughout the Limestone Coal 

 Group (Namurian) of Scotland. 



Triletes splendidus and T. indianensis 

 spores have the same type of body form, but 

 those of the former species are larger and 

 bear fewer but more robust appendages. 



By including these megaspores in the 

 genus Lagenicula, Potonie and Kremp 

 (1955, p. 119) implied a relationship with 

 the Lepidodendraceae. 



Occurrence. — These spores, not previous- 

 ly reported from this country, were found 

 in the Degonia Formation (maceration 

 200) in the upper part of the Chester Se- 

 ries, Pope County, Illinois. 



Sectio Aphanozonati Schopf, 1938 



Spores characteristic of the Aphanozonati 

 section of Triletes are large, rounded to 

 oval in outline when compressed, more 

 or less saucer-shaped originally (Schopf, 

 1941b; Chaloner, 1953c). Trilete rays gen- 

 erally are low, lacking the apical promi- 

 nence that is characteristic of spores of the 

 section Lagenicula. Arcuate ridges com- 

 monly are present, but lack flange develop- 

 ment or zonate appendages. Spore coat is 

 as a rule thick and smooth to apiculate. 

 Typical of this section are the spores of 

 Triletes glabratus and T. mamillarius of 

 sigillarian affinity (Schopf, 1941b; Chal- 

 oner, 1953c). 



Apiculate aphanozonate megaspores are 

 conspicuous in the older coal beds of both 



