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 gii'th near the base is 73 cm. 

 At the extreme summit it is only 41 cm. (LocaHty : I'l. LXXX, Xo. 62a.) 



PI. X(TI gives two views of opposite sides of the Maryland Academy 

 cycad Xo. 1, Fig. 2 showing also the summit, from a platinum print l)y 

 Mr. Smillic. 



This is the largest of the foiu- cycads at tlie museinn of the Maryland 

 Academy of Sciences. It stands 35 cm. high,l)ut being oblique at the 

 base the shorter side measures only 25 cm. It is much flattened longi- 

 tudinall}', the longer axis at the l^ase being 30 cm. and at the summit 

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

 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 light 

 angle to the axis of the trunk. (Locality: 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, j). 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, einpty 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 la,yer of spongy substance 

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

 armor 5 cm. thick; libro-cambiiun 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 strongly markc^d with longitudinal grooves; medulla distinct 

 and homogeneous, light and porous. 



