WEL WITSCHIA 
627 
Washingtonia Winsl. = Sequoia Endl. 
Watsonia Mill. Iridaceae (ill). 11 sp. Afr. , Madag. 
Weddellina Tul. Podostemaceae. 1 sp. W. squamulosa Tul., S. Am. 
The roots are more or less flattened, with haptera, and the shoots are 
borne at their edges. There are two kinds of shoots, vegetative to 2 \ 
feet long and much branched, and short unbranched flowering ones. 
Between the branches of the long shoots are branches of limited 
growth, as in Tristicha. 
Wedelia Jacq. Compositae (v). 60 sp. trop. and warm temp. 
Weigelia Pers. = Diervilla Tourn. 
Weihea Spreng. Rhizophoraceae. 10 sp. Ceylon, Madag., W. trop. 
Afr. Firs, fully hypogynous. The genus has sometimes been placed 
near to Elaeocarpus on this account. 
Weimnannia Linn. Cunoniaceae. 80 sp. S. Am., Madag., N. Z., 
Austr., Polynes. 
Wellingtonia Lindl. = Sequoia Endl. 
Welwitschia Hook. f. ( Tumboa Welw.). Gnetaceae. 1 sp., W. 
mirabilis Hook. f. (T. Bainesii Welw.), a very remarkable plant 
discovered by Baines in Damaraland in W. trop. Afr., and shortly 
afterwards by Welwitsch in Mossamedes, and described by Hooker in 
Trans. Linn. Soc. 1863 (q.v.). Specimens may be seen in most 
museums. The plant has a very peculiar habit, and grows for at least 
a century, and probably much longer. Its native climate is a markedly 
desert one, with a mere trifle of rainfall, the bulk of the moisture 
being derived from sea fogs, which cause a heavy deposit of dew. 
Seeds are produced in large quantities, and being enclosed in the 
winged perianth are blown about, and germinate in the occasional 
wet years. The stem is stout, with a two-lobed form and almost 
circular in section. It narrows downwards into a stout tap-root. 
At the edges of the two lobes are two grooves, from each of which 
springs a leaf. These leaves are the first pair after the cotyledons 
and are the only leaves the plant ever has; they go on growing at the 
base throughout its life, wearing away at the tips and often becoming 
torn down to the base. The stem continues to grow in thickness, and 
exhibits concentric grooves upon the top surface. In the outer 
(younger) of these grooves the firs, appear, in panicles of small spikes : 
they are covered by bracts which become bright red after fertilisation. 
The firs, are dioecious, and are produced annually. In the J , 
there is a perianth of 2 + 2 leaves, the outer whorl transverse to 
the bract; sta. 6, united below, with 3-loc. anthers; gynceceum rudi- 
mentary, but with the integument of the ovule looking like a style 
and stigma. In the ? , the perianth-leaves are fused into a tube, and 
are equivalent to the two outer leaves of the S ; there is no trace of 
sta. Ovule 1, erect, with the integument drawn out beyond it. Seed 
with endosperm and perisperm, enclosed in the perianth which becomes 
winged. [See Gymnospermae and Pearson in Phil . Trans. 198, 1906.] 
