40 



or petioles are rather flattened toward the base. In 

 spring (May) this tree sets up its flowers in erect, 

 short and thick panicles. The flowers are distinctly 

 yellowish, and their four petals are longer than the 

 stamens. These flowers are succeeded by a clean, 

 globose fruit, which is smooth and of a pale, rusty- 

 looking green. As you look at the smooth husk you 

 see that it is covered with fine, scale-like markings. 

 The smoothness of the fruit is one of the absolutely 

 determining features of the tree, very different from 

 the densely-prickled fruits of the ^sculus hippocas- 

 tanum, the common horsechestnut, and ^sculus glabra, 

 the Ohio buckeye, which is also pretty well covered 

 with prickles. 



Over by the northwest corner of the Arsenal you 

 will find a red maple, easily known by its generally 

 three-lobed (often five) cordate or heart-shaped bases, 

 and, alongside of it, a fine purple-leaved sycamore 

 maple. 



In the left-hand corner of the little arm of the Walk 

 that runs northward through the Arch beneath Trans- 

 verse Road No. I, you will find an excellent specimen 

 of the red buckeye Msculus pavia. Do not confound 

 this tree with red-flowered Msculus rubicunda, which 

 is a hybrid between JEscvlus hippocastanum and ^s- 

 mlus pavia. The pavia' s leaves are oblong lanceolate, 

 the rubicunda's are like those of the hippocastanum, 

 except that they come to a gradually narrowing point, 

 whereas the leaves of hippocastanum are obovate and 

 abruptly pointed. This tree here is JEsculus pavia, 

 with from five to seven leaflets of a clear shining 



