ADDISONTIA 57 
(Plate 29) 
BEGONIA WILLIAMSII 
Williams’ Begonia 
Native of Bolivia 
Family BEGONIACEAE BEGonIA Family 
Begonia Williamsii Rusby & Nash; Nash, Torreya 6: 47. 1906. 
The stems, which are usually eight to ten inches tall, arise from a 
tuberous base. The leaves rarely exceed eight on a stem; they 
have on petioles two to three inches long. The peltate, 
palmately veined blades are glabrous on both surfaces, the upper 
surface euirkecd with silvery spots; they are up to four inches long, 
the greatest diameter ee about six inches, and are lobed. The 
lobes are usually five or six, lanceolate-triangular to lanceolate, 
acuminate, the teeth siapite te. The cyme is glandular-pubescent, 
as is also the peduncle which is up to five inches long. The stami- 
nate flowers have a perianth of two parts (or rarely with one or two 
smaller and narrower inner ones) which are pellucid, green, orbicular 
or nearly ee and ii t one half inch in diameter or a little less. 
anthers are borne on sate salmon filaments. The 
e an 
ag a quarter of an inch long. The glandular-pubescent ovary 
a third of an inch long or a little less, three-celled, three-winged, 
rete of the wings truncate at the apex and narrower than the third 
wing wich has the upper edge sonehiat ase all the wings 
merging toward the rounded base of the ov he placentas 
are divi ided to the base into two somewhat curv ed blades, ovule- 
bearing to the base on both sides. The styles are persistent, about 
a fifth of an inch long, two-branched, each branch broadened and 
flattened at the base, and these margined by the stigmatic surface 
which continues spirally to the apex, and is continuous at the base 
between the two branches often as a pronounced undulation. The 
pers including the wings, is about a half inch long and a little 
This plant was discovered by R. S. Williams during his travels 
in Bolivia in 1901-2. It was found growing among moss on a damp 
shady bluff, at an altitude of 1400 feet, a short distance to the 
north of the little town of San Buena Ventura, situated on the Beni 
River which unites with the Mamore River at the southern boun- 
dary of Brazil to form the Madeira, one of the tributaries of the 
Amazon. Plants were raised at the New York Botanical Garden 
from seed secured from capsules on the herbarium specimens col- 
lected by Mr. Williams. These flowered in'January 1906, and it is 
from one of these plants that the illustration has been made. 
