THREE NEW SPECIES OF TRADESCANTIA FROM 

 THE UNITED STATES. 



By J. N. Kosk. 



The beginning; of my studies on the genus Tradescantia dates back 

 some seven years. During this time an immense amount of material 

 lias passed through my hands. The National Herbarium has undoubt- 

 edly the largest collection of American Tradescantias ever brought 

 together. For instance, we now have 110 sheets of the old T. virgin- 

 iana. Not only have I been collecting herbarium material, but I have 

 grown a number of species. 



I am now preparing a monograph of the United States species of the 

 genus, and it is my intention to illustrate all the species with colored 

 plates. A part of these illustrations have already been made. 



Botanists will confer a great favor if they will send me not only her- 

 barium specimens, but roots. I should prefer to have the herbarium 

 specimens collected this season and roots from the same clumps sent 

 late in the fall. When this can not be done the roots of flowering speci- 

 mens may be sent at once. I desire specimens not only of the rarer 

 species and of plants from out-of-the-way places, but of many of the 

 so called forms of what is generally known as T. rirginiana from all of 

 our Eastern States. Franks will be furnished upon application for 

 sending material. 



My studies of the western Tradescantias have revealed three un de- 

 scribed species. Two of these I have never seen outside of the National 

 Herbarium, while the other is not uncommon, having been distributed 

 by many collectors as a form of T. rirginiana. All three have flowered 

 for two seasons in Washington and one has been under observation for 

 four years. These species may be described as follows : 



Tradescantia humilis Rose, sp. nov. 



Stems low, K dm. or leas high, at first simple, but becoming much branched at base 

 and spreading, with more or less ronghish pubescence; leaves short, dark green, 

 oblong-linear, with rough pubescence; umbels usually several, sometimes 10, termi- 

 nating stem and branches, more or less peduneled; involucral leaves more or less 

 unequal, sometimes reduced to one, very similar to other leaves; pedicels anil ovary 

 more or less glandular; sepals narrow, acute, glandular-pubescent, and with a tuft 

 of simple hairs near the tip; petals pale blue or pink, obtuse. 

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