C.W. Ludwig Pappe studied medicine and botany at the University of Leipzig, qualifying in medicine in 1827 with a thesis on the flowering plants of the Leipzig district: Enumerationes plantarum phaenogamarum lipsiensium specimen. The thesis was published in extended form in 1829 as Synopsis plantarum phaenogamarum Lipsiensium indigenarum. Pappe arrived in Cape Town in January 1831 and was registered as a physician, surgeon and accoucheur that same year. Though he later signed all official documents as "L. Pappe, MD", he was registered on the basis of a Diploma in Physic, not the degree Doctor of Medicine (MD). Perhaps it was acceptable practice at the time for a holder of the diploma to sign himself "MD".
Pappe joined the South African Medical Society (1827-1847), the first of its kind in southern Africa, in 1832. During the measles epidemic of 1839 he was one of three doctors in charge of the temporary hospital at Cape Town, and from 1855 to 1858 was physician to the European Sick and Burial Society, and to the Widows' Fund. However, his main interest was in botany and he started collecting plants around Cape Town in the year of his arrival. His first botanical article in South Africa was published in the Nederduitsch Zuid-Afrikaansch Tijdschrift for 1833-1834 and was entitled "Systematische lijst van zoodanige Kaapse planten geslachten, als naar zulke natuurkundigen genoemd zijn die zich in de botanie vedienstelijk gemaakt hebben" (Systematic list of those Cape plants that have been named after naturalists who distinguished themselves in botany). In 1839 he married Maria (or Mary) Bam (born Mastaer or Mestaer) with whom he had five children.
In 1847 Pappe published what was probably the first paper on South African economic botany, "A list of South African indigenous plants used as remedies by the colonists", in the Cape Town Medical Gazette (1847, Vol. 1, pp. 58-63, 82-85). The paper covered over 60 plant remedies, but was based mainly on extracts from C.P. Thunberg's* Travels... of 1793. It was republished as a pamphlet entitled A list of South African indigenous plants, used as remedies by colonists of the Cape of Good Hope (Cape Town, 1847, 14 pp). A few years later it formed the basis of his Florae Capensis medicae prodromus: or, an enumeration of South African indigenous plants, used as remedies by the colonists of the cape of Good Hope (Cape Town, 1850, 32 pp). This work was intended as a commentary to a collection of Cape medicines sent to the Great Exhibition of 1851 in London by S.H. Scheuble & Co. An expanded edition appeared in 1857 (Cape Town, 54 pp) and a third edition posthumously in 1868.
Pappe was a strong supporter of the advancement of natural history in the colony, and more specifically of the movement to establish a proper botanical garden in Cape Town. He wrote a letter on the matter to the editor of the South African Commercial Advertiser in 1845, followed by two further letters describing the history of the garden established at the Cape by the Dutch East India Company. When subscriptions eventually began to be collected to finance the venture in May 1848 he subscribed £2 per annum. That same month the governor, Sir Harry Smith, appointed a commission to supervise the development of the Botanic Garden, with Pappe as one of its members. He was a great friend of Baron von Ludwig* and spent much time in the latter's famous garden. In 1849, following Ludwig's death, Pappe played an active role in acquiring trees and shrubs from the Baron's garden for the new Botanic Garden. He also collected live plants for it in the interior and obtained others from overseas, but resigned from the supervisory commission in protest when C.L.P. Zeyher*, the gardener, was dismissed in 1850.
Pappe and the colonial secretary, Rawson W. Rawson* collaborated in a study of South African ferns and published an extensive two-part paper, "Synopsis filicum Africae Australis; or, an enumeration of the South African ferns" in the Cape Monthly Magazine (November and December 1857, Vol. 2, pp. 257-287 and 359-381). The paper contained descriptions of 160 species and a classification of the genera. It was re-published as a monograph entitled Synopsis filicum Africae Australis; or, an enumeration of the South African ferns hitherto known in Cape Town in 1858 (57 pp). On 1 August that same year, having submitted a proposal to Rawson for the creation of the post of government botanist, Pappe was appointed to this position. Later in the year he also became the first professor of botany at the South African College, Cape Town. Though there was no additional salary attached to the post, he received some student fees. Before starting work at the college he undertook a collecting trip to the neighbourhoods of Tulbach and Knysna, with the result that his classes started only around April 1859. His lectures dealt mainly with introductory botany, the Linnaean classification of plants, and plant physiology. However, he was not an effective lecturer and failed to maintain discipline. From October 1860 to the middle of 1861 he was again absent on botanical tours. Around 1859 he advised the government of the United States on indigenous plants of economic value, and the government of Madras on the value of Indian millet. He investigated an outbreak of mildew in local vineyards and his recommendation that it be treated with sulpher was applied successfully.
Pappe visited the Eastern Cape several times and went to Namaqualand on his last collecting trip, in 1862. Many of the plants he collected in the western districts in 1859 and in the Eastern Cape in 1861 were sent to his friend W.H. Harvey* in Dublin, who acknowledged Pappe's assistance in the preface to Volume 1 of the Flora Capensis (1860). Pappe also made a collection of Cape algae, many species of which were described and named by K?tzing in 1858-1860. He enlarged his personal herbarium by buying Zeyher's collection. After his death his herbarium was sold to the government and formed the nucleus of the Cape Government Herbarium, later the South African Museum Herbarium, the oldest surviving herbarium in the country. Unfortunately Pappe had rewritten Zeyher's labels, often omitting the latter's collection numbers and even the collector's name, with the result that the collection lost some of its authenticity. In 1956 the whole herbarium was transferred on permanent loan to the Compton Herbarium at Kirstenbosch.
Pappe was primarily an economic botanist, but in later years interested himself also in indigenous trees and their products, which he collected in the Eastern Cape and the Knysna region. This interest led to the publication of Sylva Capensis; or, a description of South African forest-trees and arborescent shrubs, used for technical and oeconomical purposes by the colonists of the Cape of Good Hope (Cape Town, 1854, 53p). The book was mainly a commentary on a collection of 77 indigenous woods that the Cape government sent to the Universal Exhibition in Paris in 1855. An enlarged edition containing much additional information was published in London in 1862 for the purpose of the International Exhibition held in that city, to which he sent another set of 70 local woods that he had collected the previous year. However, as the Cape was not represented at the exhibition his samples were sent to the Museum of Economic Botany at the Royal Botanic Gardens, Kew. Duplicate sets were distributed to the South African Museum, Albany Museum, and museums at Port Elizabeth and Graaff-Reinet.
Pappe pointed out the dangers of deforestation and suggested measures to conserve the natural vegetation and hence the natural water resources. A paper by him on "Botanical geography and distribution of South African plants" in the Cape Monthly Magazine (October 1860, Vol. 8, pp. 237-249) was of relatively minor importance. As one of the earliest botanists who remained in South Africa until his death, his adopted country benefitted fully from his expertise and collection activities. He was succeeded as Government Botanist by J.C. Brown*.
Besides botany Pappe was interested in at least two other branches of natural history. He published an early work on South African fishes, Synopsis of the edible fishes at the Cape of Good Hope (Cape Town, 1853, 34 pp), in which 45 species were described. A second edition was published posthumously in 1866. The work was possibly inspired by the descriptions and illustrations of 41 fishes in Volume 4 (1849) of Dr Andrew Smith's* work on South African zoology. Secondly, he presented many insects (Coleoptera and Hymenoptera) to the South African museum in 1855, the year in which the museum was reconstituted. The government appointed him as one of the museum's original three trustees, a position in which he served until his death, and he also cared for and expanded its botanical collection. He accumulated an extensive personal library; in addition to books left to family members and friends a further 1342 books were auctioned after his death.
Pappe was short and stout and seems to have suffered from poor eyesight. He was a most thorough and hard-working botanist and had a good command of English, but was a diffident and introverted person. The genus of small African trees Pappea (Family Sapindaceae) was named after him by C.F. Ecklon* and Zeyher, while he was also commemorated in the species Lessertia pappeana (by Harvey) and Asplenium pappei.