318 



CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



upper surface; panicles 6 to 12 cm. long, as wide or wider, the main axis and the 

 flexuous spreading or ascending branches puberulent; spikelets 4 to 4.5 mm. long, 

 2 to 2.2 mm. wide, oblong-obovate, less turgid than in P. latifolium, papillose- 

 pubescent; first glume one-third to two-fifths the length of the spikelet, pointed; 

 second glume slightly shorter than the fruit and sterile lemma at maturity; fruit 3.2 

 to 3.5 mm. long, 1.5 to 1.6 mm. wide, elliptic, minutely pubescent, and usually black 

 at the tip. 



Autumnal form as in P. latifolium, rather more freely branching, sometimes top- 

 heavy reclining; spikelets more turgid than those of the primary panicles. 



As in P. commutation, what appear to be simple, very leafy, autumnal culms are 

 commonly formed by the replacing of the fallen primary summit by the uppermost 



branch. These culms are often 

 recurved, the blades all turned into 

 the plane of the branch, or even all 

 to one side, from a twisting of the 

 internodes, and more or less unsym- 

 metrically expanded in the middle, 

 the whole producing a very different 

 aspect from that of the vernal form. 

 This species is closely related to 

 P. latifolium and is often difficult 

 to distinguish from pubescent speci- 

 mens of that species. 



The form distinguished by Vasey 

 as P. latifolium austrah can not be 

 satisfactorily separated . The longer 

 spikelets and blades narrowed to the 

 base, or rather expanded in the 

 middleware not correlated. Specimens with large spikelets are mostly of southern 

 range, but those with blades strongly tapering to the base occur throughout, Andrews 

 40, Connecticut, being a pronounced case. The following specimens represent this 

 variation: Chase 4491, Combs 334, 337, 399, 683, Commons 361, Hall 828, Harper 1812, 

 Mohr in 1888, Nash 2329. In most of the Alabama and Florida specimens the longer 

 spikelets and tapering blades are correlated and might be given subspecific rank but 

 for the more numerous intermediate specimens. The larger spikelets and tapering 

 blades also occur in P. boscii molle. 



The following specimens are intermediate in character between P. boscii and P. 

 boscii molle, having blades more or less downy, or glabrous and downy blades on the 

 same plant: Bush 303, 310, 3348, Chase 4501, Harper 1366, Tracy 3 in 1888. 



Fig. 357. — P. boscii. From type specimen. 



DISTRIBUTION. 



Woods, Massachusetts to Oklahoma, south -to northern Florida and Texas. 

 Massachusetts: Monson, Herb. Western High School of Washington (Biltmore 



Herb.). 

 Connecticut: Southington, Andrews 40, Bissell 5552; Ledyard, Graves in 1897. 

 New Jersey: Byram Station, Fisher in 1897; Milburn, Mackenzie 2144. 

 Pennsylvania: Lancaster County, Heller 4771; Upper Darby, Smith 154. 

 Ohio: Painesville, Werner in 1886; Cincinnati, Lloyd 3597. 

 Indiana: Clarke County, Beam 5386, 6586. 

 Illinois: Marshall County, V. H. Chase 1489; Jackson County, French in 1905; 



Tunnel Hill, Ridgway in 1902; Wabash County, Schneck in 1896. 

 Missouri: Allenton, Kellogg 15; Pleasant Grove, Bush 303, 310, 323; Doniphan, 



Bush 276; Swan, Bush 26, 4534; Monteer, Bush 4652, 4908. 



