The flowering plants of South Africa; vol. 3Pole Evans, I. B. (Illtyd Buller)
Science
The flowering plants of South Africa; vol. 3
Pole Evans, I. B. (Illtyd Buller)
Plants -- South Africa -- Periodicals; Plants -- South Africa -- Pictorial works -- Periodicals
=Mesembryanthemum digitatum=, _Ait. Hort. Kew._ ed. 1, vol. ii. p.
181 (1789); _M. digitiforme_, Thunb. in Acad. Leop.-Car. Ephem.,
vol. viii. Append, p. 6 (1791); Thunb. Fl. Cap. p. 412; Fl. Cap.
vol. ii. p. 405.
This curious _Mesembryanthemum_ was first collected by Carl Thunberg
between the Oliphants River and the Bokkeveld Mountains about 150 years
ago. Thunberg described his plant in 1789, and in his herbarium there is
one sheet with two perfect growths and two flowers upon it. Marloth
(_Flora of South Africa_, Pl. 49) figures a small portion of a plant
which, he states, was collected at Van Rhynsdorp by Mr. W. Spilhaus and
was as large as a child’s head. The specimens from which our
illustration was made were collected in the same locality by Mr. E. Rood
and sent to the Division of Botany, Pretoria.
The corpuscula, which are very succulent, show an extremely interesting
structure when examined in detail. If a longitudinal section is made, a
hard green central core is seen, which is the stem; this is surrounded
by long, crystalline cells, and the whole covered in by a juicy tissue.
As the green tissue is buried in the stem, it is very probable that the
crystalline cells referred to act as lenses and concentrate any light
which penetrates the outer tissue on to the chlorophyll-bearing cells.
The fleshy leaves are almost devoid of chlorophyll.
The flower is borne at the apex of the stem, but this can only be
satisfactorily seen in a longitudinal section. The crystalline cells are
continued round the base of the calyx.
DESCRIPTION:--Acaulescent plant with woody underground stems and fleshy
aerial stems and leaves. _Stems_ 2-3 cm. long, 2-2·5 cm. in diameter,
very succulent, glabrous. _Leaves_ two to each stem, usually one larger
than the other, 1·5-2 cm. long, 0·8-1·3 cm. in diameter, terete, blunt,
very succulent, glabrous. _Flowers_ white, arising from the apex of the
stems but appearing on a casual examination to come from the base of one
of the leaves, when expanded 1·2-1·5 cm. in diameter. _Petals_ in more
than one row; the outermost row connate into definite groups, 7 mm.
long, less than 0·5 mm. broad, linear, subacute. _Stamens_ in four rows;
filaments 1 mm. long, filiform; anthers about 1 mm. long, oblong.
_Calyx_ covered with crystalline cells; lobes almost membranous, 1 cm.
long, 3 mm. broad, oblong, or oblong ovate, obtuse. _Ovary_ sunk in
tissue of stem, 5-celled, with several stalked ovules with axile
placentation; upper portion of ovary cone-shaped tipped with five
terete, acute styles each 1 mm. long.
PLATE 102.--Fig. 1, longitudinal section of stem showing sheath of
crystalline cells and flower embedded at apex; 2, longitudinal
section of flower; 3, sepal; 4, top of ovary showing the five
stigmas; 5, cross section of ovary.
F.P.S.A., 1923.
[Illustration: _103._]
PLATE 103.
BRACHYCORYTHIS PUBESCENS.
_Cape Province. Natal. Swaziland. Transvaal._
Public-domain text, read in full here on John Shaqi.
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