6 FIELD MUSEUM OF NATURAL HISTORY BOTANY, VOL. IV. 



Xanthium acutilobum Millspaugh & Sherff, sp. nov. 



Herba, veri similiter annua; caule inermi, superne setulis albis 

 scabro, setulorum basibus tuberculato-crassatis. Folia alterna, sub- 

 membranacea, circumambitu subhastato-triangulata, acute 3-y-lobata 

 et dentata, basi triplinervia et cordata aut truncata, utrimque setulis 

 albis adpressis vestita et non minutissime reticulata, petiolata, petiolis 

 adjectis 0.6-2.2 dm. longa, petiolis tenuibus et laminis subaequantibus. 

 Fructus non numerosi, maximam partem singulatim dispositi, ovato- 

 cylindrici, superne sensim in duo rostra producti (rostris minime arcua- 

 tis, ad apicem hamosis), demum badii; exteriore facie 120-180 hamosis 

 aculeis (qui 3-4.5 mm. longi et infra non solum resiniferi sed etiam 

 sparsim pilosi sunt) armati, numerosis punctis resinae punctati; fructus 

 corpore (rostris non adjectis) demum circum 1.6 cm. longo et 5-6 mm. 

 crasso; rostris infra hispidis, circum 5 mm. longis. Achenia 2; maiore 

 circum 2.1 cm. longo et 5 mm. lato; tergo levi sed altero facie 5-costato, 

 corpore sensim in basem acutum et apicem mucronatum angustato. 



J. Reverchon, Oak Cliff, Texas, September 2 (type in Herb. Missouri 

 Botanical Garden no. 85603; duplicate sheets in the same herbarium 

 bear the numbers 85470 and 85485). 



The privilege of examining the Xanthium sheets of the Missouri 

 Botanical Garden comes to us too late to allow of the preparation of an 

 illustrative plate of this species in time for this publication. In fruiting 

 involucres X. acutilobum resembles X. crassifolium, from which it is very 

 distinct, however, in its different-shaped, thinner, and much larger 

 leaves and in the characters of the achene. 



SOLIDAGO L. 



In the summer of 1917, a peculiar specimen of Solidago came to our 

 notice. It had been collected by Isaac Holton near Morris, Illinois, 

 September 13, 1850, and during all the years since then had remained 

 with merely the name Solidago upon its label. In its inflorescence it 

 suggested at once 5. speciosa Nutt., especially the smaller form of that 

 species often termed var. angustata T. & G. (5. rigidiuscula Porter). 

 But the heads were noticeably smaller than heads of the same degree 

 of maturity in any material of S. speciosa. The leaves did not possess 

 the pronounced reticulation that is so characteristic of the leaves of 

 S. speciosa; and, what was still more striking, the lower leaves were 

 cuneate-oblanceolate in outline and distinctly notched at the apex. 



By reference to other material collected by Holton on the same 

 day, it was learned that he had collected at least one plant that day 

 along the Illinois-Michigan canal (Aster sericeus Vent.). Trips were 

 made to Morris on September 8 and September 23, 1917, for the express 



