The flowering plants of South Africa; vol. 3

Cape Province.

Ficoideae. Tribe Mesembryeae.
Mesembryanthemum, Linn.; Benth. et Hook. f. Gen. Plant. vol. i. p. 853.

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.

Cape Province. Natal. Swaziland. Transvaal.

Orchidaceae. Tribe Ophrydeae.
Brachycorythis, Lindl.; Benth. et Hook. f. Gen. Plant. vol. iii. p. 632.

Brachycorythis pubescens, Harv. Thes. Cop. i. 35, t. 54; Fl. Cap. vol. v.
sect. 3, p. 86; Bolus, Orchids of S. Afr. tab. 73.

The genus Brachycorythis is represented in Africa by over twenty species, five of which occur in South Africa, and of these three are endemic. The species described here is known from the Cape Province, Natal, Zululand, Swaziland and the northern Transvaal, and extends into tropical Africa. Its occurrence near Pretoria, in a totally different botanical area, is therefore interesting. Harvey first described the plant from specimens found near Durban by Mr. Sanderson, who stated it was plentiful in the neighbourhood.

This attractive little orchid was collected by General the Rt. Hon. J. C. Smuts on the farm Rietvlei No. 221, at Irene, near Pretoria, at an altitude of about 5000 ft. above sea-level. The plant was found in open grassland in deep red loam soil. It has large spreading finger-like tubers and slightly scented flowers.

Natal.

Acanthaceae. Tribe Justiceae.

MacKaya, Harv.; Benth. et Hook. f. Gen. Plant. vol. ii. p. 1095 (under
Asystasia).

MacKaya bella, Harv. Thes. Cap. i. 8, t. 13; Fl. Cap. vol. v. sect. 1,
p. 44; Wood, Natal Plant. t. 585.

This plant was discovered in Natal by Mr. J. Sanderson, who sent living specimens to Kew, where it flowered first in May 1869. From the material a figure of the plant was published in the Botanical Magazine of the same year. This figure, however, does not accurately represent the plant as it is known in its native habitat and in local cultivation. The flowers are lilac, and not almost white, as indicated in the Botanical Magazine. The late Dr. Medley Wood reproduced a pencil drawing of the plant in “Natal Plants” in 1912, and states it “is a handsome shrub, but it is of no economic value; it is found only in the coast and midland districts of Natal, and does not seem to be very common.” MacKaya bella differs from Crossandra Greenstockii (see Plate 77), which also belongs to the Acanthaceae, in having almost a regular, not a 1-lipped corolla.

Dr. Harvey, who first described the genus, dedicated it to Dr. J. T. MacKay, keeper of the Dublin University Botanic Garden. Our figure was prepared from plants growing in the “Flanagan Arboretum,” Union Buildings, Pretoria.

Transvaal. Cape Province.

Apocynaceae. Tribe Echitideae.
Adenium, Roem. et Schult.; Benth. et Hook. f. Gen. Plant. vol. ii. p. 722.

Adenium oleifolium, Stapf, var. angustifolium, Phillips var. nov., a
typo foliis angustis differt.

The genus Adenium is represented in South Africa by three species found in the Transvaal, Swaziland and the North-Western Cape Province. Species of the genus are also found extending through tropical Africa to Socotra. On Plate 16 we figured Adenium multiflorum, from which the present plant differs in having long narrow leaves; both, however, have very large tuberous underground stems from which the branches arise. The peculiar tailed anthers and the scales in the corolla-throat which sometimes form small pouches are characteristic of the genus.

Specimens were submitted to Kew for confirmation of the name, and the Director reports “very probably A. oleifolium, Stapf, but leaves are much narrower than in the type,” and it was thought advisable to describe this as a narrow-leaved variety.

Our plate was prepared from specimens collected by Dr. W. M. Borcherds at Upington, and forwarded by him to the Division of Botany, Pretoria.

Transvaal.

Scrophulariaceae. Tribe Gratioleae.
Craterostigma, Hochst.; Benth. et Hook. f. Gen. Plant. vol. ii. p. 954.

Craterostigma plantagineum, Hochst. in Flora, 1841, 669; Fl. Cap.
vol. iv. sect. 2, p. 361.

The Craterostigma figured on the accompanying plate is known from various localities in the Transvaal. It is also recorded from the neighbourhood of Bulawayo in Rhodesia and from other parts of tropical Africa reaching as far north as Arabia and Abyssinia. The genus is mainly a tropical one, and is represented by about a dozen species, three of which are found in South Africa.

C. plantagineum is a charming little plant which would be well worth cultivation in the greenhouse and should be easily grown. Our plate was prepared from specimens collected by Dr. I. B. Pole Evans, C.M.G., on the portion of the farm Rietfontein 448, near Pretoria, belonging to Mr. J. F. Ludorf. The plants were found growing in great profusion in shallow soil not more than one inch deep on a large quartzite outcrop. They were in flower during November and December.

Cape Province.

Liliaceae. Tribe Aloineae.
Aloe, Linn.; Benth. et Hook. f. Gen. Plant. vol. iii. p. 776.

Aloe comosa, Marloth and A. Berg. in Engl. Bot. Jahrb. vol. 38, p. 86.

The Aloe which forms the subject of this plate is, so far as is known, only found on the Bokkeveld beds in the Clanwilliam and Van Rhynsdorp Districts of the Cape Province. Full-grown plants attain a height of 12-15 ft., and when in full bloom, which is usually during December and January, their long massive inflorescences make such a display of colour in the veld that they cannot fail to attract the notice of the traveller. As will be seen from the illustration, the uppermost flowers are hidden by the long bracts, the flowers in the middle portion of the inflorescence are pink and spreading, while those at the base are pendulous and greenish-white. The stamens are only exserted from the pendulous flowers, and after pollination the filaments contract and are withdrawn into the perianth, which closes round them, leaving the style exserted. This phenomenon is also found in Aloe saponaria figured on Plate 96, and is probably fairly general in the genus Aloe.

The material from which our plate was made was collected by Dr. I. B. Pole Evans, C.M.G., on the Doorn River near Van Rhynsdorp, and brought to Pretoria, where the plants flower regularly every year during December and January. Aloe comosa was first collected and described by Dr. R. Marloth, who found it between Clanwilliam and Van Rhynsdorp in 1904.

Cape Province.

Proteaceae. Tribe Proteae.
Protea, Linn.; Benth. et Hook. f. Gen. Plant. vol. iii. p. 169.

Protea pityphylla, Phill. var. latifolia, Phillips var. nov., a typo foliis
latis differt.

The Protea figured on the accompanying plate is readily distinguished from the species by its flat, linear leaves, and on this character alone has been described as a variety of P. pityphylla, Phill. We are indebted to Miss L. Guthrie of the Bolus Herbarium for the specimens, which she received from Mr. de Wet of Ceres. The plant is stated to grow in the same habitat and to be found associated with P. pityphylla and P. Marlothii. It has the characteristic involucre of the former species, namely, the long leaf-like appendages from the apices of the lowermost bracts and also the same pendulous heads. The section of the genus (§ Pinifoliæ), comprising species with narrowly linear, filiform or needle-shaped leaves, to which this plant belongs is illustrated here for the first time.

Transvaal.

Malpighiaceae. Tribe Hirrae.
Triaspis, Burch.; Benth. et Hook. f. Gen. Plant. vol. i. p. 259.

Triaspis Nelsoni, Oliv. in Hook. Ic. Pl. t. 1418.

Triaspis Nelsoni was first described and figured in 1883 from material collected by Mr. W. Nelson at Pretoria. The figure given by Hooker is incorrect in a few small details. The pedicels, for instance, are articulated and bear 2 small bracteoles; the three styles are not equal, but one is longer than the other two and is deflexed at an angle of about 45°; the anterior petal is exterior in the bud and larger than the other petals.

The genus Triaspis is found in Madagascar, tropical and southern Africa, and was first recorded by the famous traveller Burchell, who collected specimens of a plant he described as T. hypericoides at Kosi Fountain in Bechuanaland in 1812. Since then several species have been recorded from the Transvaal.

The species figured on the accompanying plate is of frequent occurrence on the soils overlying the dolomite outcrops south of Pretoria at an elevation of 4000-5000 ft. above sea-level. It forms a subherbaceous bush not more than two feet high, and the main branches always tend to droop. When in flower it is a most attractive and beautiful object in the veld, and is well worth cultivation in our gardens. In addition to the beauty of its flowers, its large copper-coloured orbicular winged fruits add considerably to its charm and gracefulness. The material from which our plate was prepared was collected by Dr. I. B. Pole Evans, C.M.G., on the farm Doornkloof, Irene, near Pretoria, belonging to General the Rt. Hon. J. C. Smuts.

Cape Province.

Ficoideae. Tribe Mesembryeae.
Mesembryanthemum, Linn.; Benth. et Hook. f. Gen. Plant. vol. i. p. 853.

Mesembryanthemum Pillansii, Kensit in Plant. Nov. Hort. Then. II.
tab. 57 (1908); Botanical Mag. t. 8703.

Dr. R. Marloth supplies the following interesting note on this plant. “Originally found by Mr. Eustace Pillans (not Mr. N. Pillans, as stated in the Botanical Magazine) on the farm Mouton Valley on the Piquetberg mountains to the north-west of Piquetberg.

The present plants were gathered by me at the same locality in October 1922 on sandstone hills among Protea trees (waabom, P. grandiflora), forming shrublets 1½ to 2 ft. high with erect virgate branches.

The description in the Botanical Magazine is fairly correct, but the coloured petals are all radiating on the wild plants (not some erect and conniving, as stated in the Botanical Magazine for the cultivated plants). They are arranged in 5 groups in front of the sepals. The stigmata are distinct and papillate in the later stages of the flower.

The plant is easily cultivated at Cape Town, and I have had it in flower for several years from September to December.

The flowers are of special biological interest. The stamens do not stand erect as in most other species, but are incurved towards the centre to such an extent that the filaments from opposite stamens meet and the anthers are consequently enclosed in the lentil-shaped cavity thus formed above the concave apex of the ovary. The roof of this cavity is further strengthened by the filiform white inner petals which possess a rough surface and are also tightly incurved inwards, meeting at the centre.

Cape Province, Swaziland, Transvaal.

Liliaceae. Tribe Aloineae.

Aloe, Linn.; Benth. et Hook. f. Gen. Plant. vol. iii. p. 776.

Aloe microcantha, Haw. Suppl. 105; Fl. Cap. vol. vi. p. 306; Sims in
Bot. Mag. t. 2272.

Aloe microcantha, which forms the subject of the accompanying plate, occurs frequently in the open grass veld along the eastern mountain range from Grahamstown northwards as far as the valley of the Limpopo. In Swaziland and the eastern Transvaal it is usually found along the edges of streams and in marshy places. In localities of high rainfall, such as Haenertsberg on the Drakensbergen in the Transvaal, this plant is often a conspicuous and beautiful object on the grassy slopes facing east. It flowers during January and February. As soon as the seed has set, a few months later, the leaves wither almost completely to their bases, leaving a short stem surrounded by a few dried leaves to weather the winter drought.

We are indebted to Mr. Chas. Maggs of Pretoria for the specimen figured in our illustration. It was collected by Mr. Maggs on his Waterval Estate, near Sabie, on the Drakensberg, in January 1921, and forwarded to the Division of Botany, where it flowered in January the following year.

Aloe microcantha was first collected by Bowie and introduced into cultivation in 1819. It was figured in Curtis’ Botanical Magazine in 1821 as a plant of great rarity from the Cape of Good Hope.

Cape Province, Natal.

Leguminosae. Tribe Phaseoleae.

Erythrina, Linn.; Benth. et Hook. f. Gen. Plant. vol. i. p. 531.

Erythrina Humeana, Spreng. Syst. iii. 243; E. Humei, E. Mey. Comm.
Pl. Afr. Austr. 150; Fl. Cap. vol. i. p. 237.

In a previous issue, on Plate 59, we figured the Kaffir Boom (Erythrina caffra), from which the present species differs in being of a dwarf habit and having the nerves of the leaves and petioles covered with prickles. It is a common plant on the slopes of the Drakensberg in Natal, extending southward to Grahamstown, and during the summer months the bright red flowers are very conspicuous in the veld. The leaves of this species, as well as those of E. caffra, are attacked by a gall-producing insect, and the seeds are attacked by insects to such an extent that it is difficult to find ripe seed.

The species has been known to cultivators in Europe for over 100 years, and was figured in the Botanical Magazine as early as 1823. It is a very handsome shrub which stands from 4 to 8 ft. high, and is well worth cultivation.

Transvaal.

Passifloraceae. Tribe Modecceae.

Adenia, Forsk. Fl. Aegypt. Arab. 77 (1775).

Adenia digitata, Engl. Bot. Jahrb. vol. xiv. p. 375; Modecca digitata,
Harv. Thes. Cap. t. 12, 167; Fl. Cap. vol. ii. p. 499.

The species of Adenia described below and figured on the accompanying Plate is of special interest, inasmuch as the large tuberous roots have proved to be extremely poisonous. In October 1922 the plant was brought to the notice of the Division of Botany by Dr. H. Osborne of Pretoria, who reported that two white labourers were admitted to the Pretoria Hospital suspected of having been poisoned by eating a portion of the root, and that one of them died shortly after admission to the Hospital. A sample of the root sent in by Dr. Osborne was submitted to Drs. H. H. Green and W. H. Andrews of the Division of Veterinary Research, and as a result of their investigations two types of poison were discovered. One of these acts very rapidly, and with symptoms which can be attributed to the small amount of a cyanogetic glucoside; the other acts more slowly, but its chemical nature is as yet unknown. A full account of these investigations will be published in the Report of the Director of Veterinary Research.

The fruits of Adenia digitata are berries of a very attractive nature, and also appear to be poisonous, for some years ago in the Pretoria District two native children died after eating them.

The plant is quite common in the Pretoria District, and also occurs in the Barberton District. It has long, graceful branches provided with tendrils, by means of which it climbs up neighbouring bushes and shrubs.