The Journal of Indian Botany/Volume 2/October 1921/Lantana in Ceylon
LANTANA IN CEYLON.
BY
T. Petch
Peradeniya, Ceylon.
In Memoirs of the Department of Agriculture in India, Vol. V, No. 6, Rao Sahib Y. Ramachandra Rao has presented a paper on Lantana insects in India which is of interest to botanists, as it includes a comprehensive account of the host plants, one at least of which, Lantana aculeata, is a troublesome weed in many parts of the Eastern Tropics.
As regards the status of Lantana, Ceylon constitutes an exception to the general experience. In Ceylon, Lantana aculeata is common enough, but it is not looked upon as a troublesome weed. Indeed, the tendency is rather to regard it as beneficial, since it rapidly takes possession of waste ground and thereby prevents denudation or deterioration of the soil by exposure.
Ceylon, however, comes in for special consideration by investigators of the Lantana problem, as the possessor of a plant, Tithonia diversifolia, which is alleged to kill out Lantana. This idea appears to have originated about 1890, and it was given currency outside Ceylon by Mr. John Ross, a resident in Hawaii, who published a note on the subject in the Planters' Monthly (Bonolulu), vol. X, pp. 436, 437 (October, 1891).
Mr. Ross had met Lieutenant-General Sir Allen Johnson "of the British Army in India" and, on explaining to the latter how " Lantana was fast getting a ruinous control of the best pasture lands," was informed by him that in Ceylon "they were having a similar experience to us, but that lately they were getting it under control through the agency of a particular kind of sun-flower imported there." In consequence, Mr. Ross communicated with Ceylon, and obtained seeds of the sunflower in question, accompanied by a letter from Trimen, from which the following extract was published (loc. cit.).
"The plant referred to by Mr. Ross is, no doubt, the Californian sun-flower, Tithonia diversifolia, the brilliantly yellow-flowered weed so conspicuous on waste ground in Ceylon.
"I have recently pointed out to several visitors here the curious fact that, when growing along with Lantana, this gradually kills out the latter; the modus operandi obviously being that it grows taller, and, by its large leaves, keeps out the sunlight, without which the Lantana cannot exist. No doubt some report of this has been carried to Hawaii. I do not think, however, that Tiihonia has ever yet been sown in Ceylon with the object of destroying Lantana; indeed, one weed is little better than the other.
There is no difficulty in obtaining seed in any quantity.
Henry Trimen,
Colombo, Director, Royal Botanical Gardens.
- August 15th, 1891.
Trimen does not appear to have made any direct publication on the subject.
Ceylon botanists at the present time would hesitate to affirm that Tiihonia kills out Lantana to any marked extent, though where the two grow together the process described by Trimen may operate. This is assisted on waste land by the side of the railway by the periodic cutting back of the vegetation, as Tiihonia develops a large stool from which new shoots spring up rapidly after cutting and smother slower-growing species. But Tiihonia appears to prefer damper localities than Lantana. It is especially luxuriant along the banks of rivers, and here in many cases it occupies the lower parts of the sloping banks while Lantana flourishes in the drier upper parts. As regards their relative status as weeds, — it is more difficult to get rid of Tiihonia than Lantana, because of the more extensive develop- ment of the rootstock of the former.
Tiihonia diversifolia was not introduced into Ceylon with the object of killing out Lantana. It was introduced as a garden plant in 1851, and soon escaped from cultivation. Seeds were, however, sent to Hawaii for that purpose.
The author of the Memoir states that Lantana is reported to have been introduced into Ceylon about 1824 and that it is probable that it reached India about the same time. It is very difficult to fix the dates of introduction into Ceylon of the earlier exotics, as few of the early records are extant. This is no doubt due in part to the frequent changes of Superintendents during the twenty-five years following the removal of the Botanic Garden to Peradeniya, as these changes must have made it impossible to establish any proper organ- isation. Moreover, owing to lack of adequate office room and furni- ture, records were stored in cases on the verandah of the Superinten- dent's bungalow, where they were inevitably destroyed by white ants. There is also the further extenuating fact that on the death of each
862—40 successive Superintendent, — and six died between 1825 and 1849 — all papers were removed to the Kachcheri in the neighbouring town of Kandy; and three removals being as bad as a fire, they probably suffered some loss in consequence.
The approximate dates of introduction of the earlier species were worked out by Trimen, and included by him in his Hortus Zeylanicus (1888). These were deduced chiefly from the records and specimens of botanists who visited Ceylon before the establishment of a Botanic Garden. For example, if Trimen stated that a given species was introduced before 1678, that means that the species was recorded or collected by Hermann. Similarly, the date 1824 signi- fies that the plant in question was enumerated by Moon in his Catalogue of Ceylon Plants. Moon's records, however, are to be accepted with reserve, as in very few cases are there any specimens in support of them.
The first record of Lantana for Ceylon was made by Moon, who recorded Lantana trifolia, as an introduced plant, in his Catalogue published in 1824. As it is included in the Additions, not in the main body of the Catalogue, it was probably introduced while the book was in the press. Moon cites Bot. Mag. t. 1449, hence it is assumed that his identification was correct. But Moon's plant, Lantana trifolia, is a common weed only at high elevations ; it is not the common Lantana of the low country.
Colonel and Mrs. Walker who enumerated the plants met with between Ratnapura and Adam's Peak in the Colombo Journal, 1833, did not mention Lantana. Again, Mrs. Walker, in describing a tour in the low-country in Hooker's Journal of Botany, II (1840), pp. 223- 256, made no reference to it. Champion (Hooker's Journal of Bot- any, III (1841), pp. 282-292) recorded that Lantana aculeata occurred round Colombo in 1839 ; and in 1843, he enumerated Lantana sp. among the predominating shrubs and plants from sea level to 2,000- 3,000 ft. As the native Lantana indica is very rare in Ceylon, the latter record is not likely to refer to that. Finally, Gardner, in "Some general remarks on the Flora of Ceylon ' (1848), referred to " The Lantanas which are to be met with almost everywhere in bushy places and hedges."
Trimen did not assign a date to the introduction of Lantana aculeata in his Hortus Zeylanicus (1888). In the Flora of Ceylon, III, p. 346, he stated that it was introduced soon after 1824 and added that its introduction was attributed to Sir Hudson Low, who held a military command in Ceylon in 1826. As it had become a weed by 1839, the suggested date is probably correct. As regards the introduction of Lantana into India, it is to be noted that Hortus Bengalensis (1814) records Lantana trifolia, presented to the Garden by Dr. W. Carey in 1807, and Lantana aculeata, presented by W. Hamilton in 1809. Thus both plants were known in India many years prior to their introduction into Ceylon, and, taking into account the fact that in the early days of the Ceylon Botanic Garden the bulk of its accessions were obtained from India, it is most probable that both were introduced into Ceylon from India.
The colour of tbe flowers of Lantana aculeata changes from orange-yellow to red as the flower matures. Some years ago, the ques- tion was raised by an entomologist whether the colour change was related to pollination, and, though that did not appear probable, the following tests were carried out.
An inflorescence was enclosed in a glass tube which was plugged with cotton wool. Care was taken to see that no insects were pre- sent. The flowers expanded normally, the colour change of the in- dividual florets occurring in two to three days. No achenes ripened. This was repeated with two more inflorescences with the same result. The colour change is, therefore, independent of pollination. Two inflores- cences which were left free during the same period ripened three and five achenes respectively.
[Note. — With regard to the name to be adopted for the common Lantana, the following notes may be of interest from a historical standpoint, though the final settlement must depend upon an exami- nation of the material on which the Linnaean citations were based, and a determination of the plants in their native country. I am not aware of any recent discussion of the question.
According to Systema Naturae, Ed. XIII (Gmelin 1791), Lin- naeus distinguished Lantana aculeata and L. Camara as follows, —
Lantana aculeata, foliis oppositis, caule aculeato ramoso, spicis hemis- phaericis. Mant., p. 419. Plukn., Aim., t. 233, f. 5. Gaertn., de fr. et sera., cent. 4, t. 56, f . 4.
Lantana Camara, foliis oppositis, caule inerme ramoso, floribus capitato- umbellatis apbyllis. Dill., H. Elth., t. 56, f. 65.
Schauer, in DC. Prod., XI (1847), made Lantana aculeata L. a form of Lantana Camara L., " forma caule magis aculeato ; " and described L. Camara as " ramis patentibus tetragonis cum pedunculis pubescentibus vel hirto-pilo- sis aculeatis subinermibusve scabris." He cited tbe figure in Dillenius, Hort. Eltb., but not that in Plukenet. According to Schauer, L. camara may be prickly or not. It would seem that this point can only be decided in America : certainly the Ceylon form is always prickly.
Thwaites, in Enumeratio Plantarum Zeylaniae (1861), assigned the Ceylon Low-country weed to Lantana mixta L. This was apparently an error. L. mixta L., fide Schauer, is distinct from L. Camara L. and L. acul- eata L. C. B. Clarke, in Flora British India, IV, p. 562, (1885) followed Schauer referring the common Indian and Ceylon plant to Lantana Camara L, and citing its previous identifications as Lantana aculeata L. in Roxb. Hort. Beng. 46, and as L. mixta L. in Thwaites, Enum. Plant. Zeyl., 242.
Trimen, Handbook of the Flora of Ceylon, III, p. 346 (1895), wrote "With regard to the right name for this common weed, L. mixta L. is adopted by Thwaites, and L. Camara L. in Flora British India, IV, 562 ; but our plant is always prickly, and is well represented in the figure quoted by Linnaeus for his L. aculeata (Plukenet, Phyt., t. 233, f. 5), made from a plant then (1696) in cultivation at Hampton Court."
Cooke, Flora of the Bombay Presidency, II, p. 419 (1905), follows Flora British India in adopting the name L. Camara L. for the prickly species with orange-coloured flowers, and cites L. aculeata L. as a synonym.
Ceylon botanists have followed Trimen in regarding L, aculeata as dis- tinct from, not a form of, L. Camara. In Ceylon we have, as far as has yet been recorded, only the yellow-red-flowered form of this species.
T. PETCH.