THE AMERICAN BOTANIST 151 



best, these crystals must be formed when there is a slight 

 movement of the air, being built up on the windward side of 

 objects from the supplies of moisture constantly brought to 

 them. The silver thaw happens when the air is filled with the 

 silvery shimmering frost crystals formed high above the earth 

 after a cold night in winter. A scientific classification of pre- 

 cipitation forms include the sweating of stones and walls, dew. 

 mist, fog, rime, hoar frost, mist ice, rain, snow, hail and sleet, 

 but the silver thaw is the most beautiful of all both in title and 

 appearance. 



Vernacular Names. — It is very probable that many of 

 the vernacular names cited in our manuals are not now in use 

 in the United States except as they are learned from the 

 manuals themselves, that is, they are book names, and un- 

 doubtedly hundreds. of vernacular names in more or less com- 

 mon use are unrecorded. Scores of "common names" have no 

 existence except in print, being often a mere translation of the 

 Latin names. How much better it would be to cite an actually 

 used vernacular name, even if known only in a limited region, 

 than to coin a name by the simple process of translating the 

 Latin one and thus establishing in print a name that nobody 

 ever uses. Yet probably no herbarium in the United States 

 gives any appreciable amount of data as to vernacular names 

 actually in use, for the simple reason that botanists and col- 

 lectors have neglected to record such names with the specimens. 

 — E. D. Merrill, in Science. 



A New Form of Rudbeckia Hirta. — In an old upland 

 pasture at Vaughns, north of Hudson Falls, New York, where 

 the black-eyed Susan has been very abundant for several years, 

 an interesting form was found July 28, 1916, which may be 

 called Rudbeckia hirta f. iiridiflora. It is like the type, except 

 that the orange-yellow rays are partly or wholly green. The 

 type is in my collection. In some of the flowers only the lower 

 part of the ray was green, or green along the center of the ray : 



