432 MESOZOIC FLORAS OF UNITED STATES. 



tion at the summit. The short diameter is nowhere more than 12 cm. and 

 averages less than 10 cm. The maximum girth near the base is 73 cm. 

 At the extreme summit it is only 41 cm. (Locahty : PI. LXXX, No. 62a.) 



PI. XCII gives two views of opposite sides of the Maryland Academy 

 cycad No. 1, Fig. 2 showing also the summit, from a platinum print by 

 Mr. Smillie. 



This is the largest of the four cycads at the museum of the Maryland 

 Academy of Sciences. It stands 35 cm. high, but l^eing oblique at the 

 base the shorter side measures onl}^ 25 cm. It is much flattened longi- 

 tudinally, the longer axis at the base being 30 cm. and at the summit 

 22 cm. The minor axis is 19 cm. at the thickest part, near the middle, 

 but the sides are irregular and the average is not over 15 cm. The girth 

 is about 71 cm., except near the top, where it is 63 cm. The base is 

 oblique in the direction of the major axis and the summit in that of the 

 minor. It is thoroughly silicified and of a light color, reddish or pinkish 

 and even dark in some places, much worn on all sides, rough and irregu- 

 lar on the surface. The leaf scars penetrate the armor at about a right 

 angle to the axis of the trunk. (Localit}^: PI. LXXX, No. 46.) 



Cycadeoidea Tysoniana Ward. 



PI. LXXXVII, Figs. I, 5; v, 4; PI. XCIII. 



1897. Cycadeoidea Tysoniana Ward: Proc. Biol. Soc. Washington, Vol. XI, p. 11. 



Trunk medium sized or large, more or less compressed laterally; 

 leaves slightly ascending; leaf scars arranged in spiral rows, 9 mm. high, 

 22 mm. wide, subrhombic, empty to some depth, petioles persistent at 

 base, the vascular bundles arranged in one row near the exterior and a 

 group near the center, often persisting after the decay of the remaining 

 substance; ramentum walls thin, often with a layer of spongy substance 

 in the middle, wrinkled on the edges; reproductive organs few and small; 

 armor 5 cm. thick; libro-cambium zone sometimes distinct, 3 mm. thick; 

 woody zone 6 cm. to 8 cm. thick; consisting of a broad, parenchym- 

 atous layer 4 to 6 cm. thick, and a narrow inner vascular zone 1 cm. 

 thick, the latter usually between open tissue without and within, its 

 inner wall strongl}^ marked with longitudinal grooves; medulla distinct 

 and homogeneous, light and porous. 



