THE HISTORY OF PRIMULA 3/ffALACOIDES, FRANfJHET, UNDER OULTIVATION.

Bt, AI~THUR W. HILL.

(With Plates XI and XII and one Text-figure.)

THE history of Primula malaeoides under cultivation is of some interest, as ~hough of only recent introduction it has been very exten- sively grown in this country and has already displayed a considerable range of variation. The species was discovered by Phre Delavay in Narch, t884,, in cultivated fields at Tall, Yunnan, a locality to which it appears to be restricted, and a description of the plant was drawn up by Franchet in 18861. The introduction of the plant to cultivation is due to l~r G. Forrest; who collected specimens in the Tall valley in 1905 and 1906. From the seed sent home to 1Vfr Bully of Ness (of the firm of Nessrs , Ltd, of Liverpool, for whom Mr Forrest was collecting) plants were raised which flowered in 1908-". Nr Forrest records that it is abundant in the Tall valley near the city at elevations of fl'om 5000 to 7000 feet, and that it was thriving in rather moist sunny situations. The illustration of a plant raised by Nessrs Bees in 1908 is given in Notes of the Royal Botanic Garden Edi,~burgh, Vol. IV. P1. XXVII B, and shgws the slender, graceful inflorescenees of the original plants 3. A figure of a more robust specimen is given in the Gardener's Magazine for Dec. 5, 1908. The plant figured was shown by Messrs Bees, Ltd, and given an award of merit at the meeting of the Royal Horticultural Society's meeting of Nov. 24.

I :Pranehet, in Ball. See. Bet. Ft. Vol. xxxm. 1886, p. 64. 2 Messrs Vilmorin had received seeds in 1895 they failed to germinate. a The s0,me figure is reproduced in ~he G(~rde~ters' Chrowicle of Dec. 5, 1908, p. a97, in connection with ~ short note on the plant by Prof. Bayley Br~lfour. 194 History of Primula malacoides, Franchet

According to Franehe~'s original description the colour of the wild flowers is and the limb of the Corolla is said to be 10m12 mm. in diameter Prof, Balfour in his note in 1908 says : "To some its tint of pink lavender-pink, in contrast with the grey mealy surNee of the flower stems, will be haMly pronounced enough for effect, but time and culti- vation will alter that, and it may be precl~eted that this Primula is likely to bee0me a general favourite .... " This prophecy was quickly Nlfilled. It lnay be remembered that in the ease of Prim~da obconica ~ no s~riking variations occurred until the plant had been in cultivation for some fifteen years, and double flowers were only developed in the twenty-first year of its cultivated existence. With P. malacoides however the whole range of variations was initiated in about four years fi'om the date of its introduction to this country. A figure in The Gardens"- for 1912 shows the more robust character of' the plant as compared with those first cultivated in this country. The only eoloured illustration of P. malacoides of which we are aware is that published in the Revue Horticole for 1912, p. 156, which depicts a plant very like the type as originally introduced. The plant does not appear to have been cultivated in France unl)il 1911 when it was exhibited by iessrs Vilmorin at a meeting of the French Horti- cultural Society in the spring of that year ~. M. Mottet, the author of the article, gives a short historical account of ~he plant and, what is of considerable value, has 'drawn up a detailed description from living specimens cultivated in Paris in 1911. According to this description the corolla measured 15--20 ram. across, the segments were deeply notched and the eolour was a soft rose-lilac with a gu'eenish-white centre. The leaves were 6--8 em. long, oval rounded at the apex and eordiform at the base, The leaves on our collected specimens are up to 9 em. long From this account it appears that the effect of cultivation has been to increase the size of the flowers fi'om the maximum of 12 ram. in diameter given by Franchet to 25 ram., which is the dimension of the lar.gest flower yet, noticed. In England about this time apparently the plant varied in several directions. Messrs Sutton and Sons sent to Kew on April 6, 1912, a

A. W. Hill, "The history of Primula obconica, Hance, under cultivation, &o." in Jom'm Genetics, gol n 1912, p. 1, with plates. '-' The Garden, M~roh 30, 1912, pp. 157, 158, with fig. l~ev. IIort 1911, p. 218; Journ. Soc. Nat. IIort. lrr. 1911, p. 181. AP~THUI~ W. HILI~ 195 white sport of P. malacoides (P1. XI, Fig. 3) and informed us that they had also a "deep mauve quite distinct from the type." The flowers of the white sport measured only 1 cm. across, the corolla segments were narrow, only 4 ram. broad at the apex and almost oblong with a shallow notch. The eye was deepyellow. The calyces were very mealy and the infloreseenees much more slender than in the type. Messrs Bees, Ltd, who also had the white sport, remarked that the habit of the plant is very distinct fi'om that of the rose-eoloured form, the inflm'eseenees being much more erect and the distances between the whorls of flowers much shorter. The flowers of the white form sent by them to Kew measured 2 era. across, whilst the largest lilac flowers measured 2"5 era. The more robust character attained by the plant in its fifth year of cultivation is well shewn in the figure in The Garden for March 30, 1912, p. 157, In this same year P. malacoides also produced double flowers for the first tim'e, and this sport occurred among a large batch of plants grown by Mr L. R. Russell at his Cedar Nursery, Ham, Surrey (P1. XI, Figs. 5--12 ; P1. XII, Figs. 2 and 3). All stages in the doubling of the flowers were noticed, and on the same inflorescence in Some plants every gradation from single to fully double flowers could be found. The doubling is like that of the old double white P. sinensis and of P. ob- conics, being due to out-growths from the apex of the connective of the anther resulting in a "hose-in-hose" type of flower. In the best cases one or more whorls of extra segments have been developed, each seg/nent having the characteristic apical notch. A good figure of the double form was given in The Garden of Dec. 13, 1913, p. 624, from a plant grown by Nessrs Bees, Ltd, and the sport appears to have originated in Cheshire independently of its appearance at Messrs Russell's nursery ~. The double white variety was produced at Kew as a result of crossing the double lilac with the single white form and flowered in 1915. This spring (1917) Messrs W. and J. Brown of Stamford, showed double white', double lilac and double mauve forms at a meeting of the Royal Horti- cultural Society.

1 Although the double form of P. malacoides originated first with lglessrs Russell in 1912 it was Messrs Bees' plant shown at the meeting of the R. H. S. on December 2, 1913, which received an Award of Merit, see G. C. March 14, 1914, p. 180. e A figure of the double white form is given in Gardeners' Chronicle, March 2, 1918, p. 91, and the foliage of the plant is distinctly "fern-like." 196 History of Primula malacoides, Franchet

The seed of these three doubles was obtained fi'om a private grower and sown in the autumn of 1916. Another break which occurred in 1912 also at Messrs Russell's nursery consisted in the fimbriation of the corolla segments, a variation which has commonly developed in primulas under cultivation (P1. XI, Fig. 13 ; P1. XII, Fig. 4,). In the examples seen in 1912 the apical notch still existed, but the lobes of the segment were more o1" less deeply cut or laciniated and there was also a tendency to the formation of tooth-like pl'ojections in the sinuses between the segments. This latter tendency is especially noticeable in the forms with narrow segments ~nd wide sinuses (P1. XI, Fig. 15 ; P1. XII, Fig. 5). In some cases only a single segment or one side of a segment of a flower may show fimbriation. With fimbriation of the corolla is associated also a fimbriation of the calyx. [Normally the calyx five simple acute teeth, but where the ,corolla segments are laciniate the calyx teeth tend to be conspicuously and sharply toothed (P1. XI, Figs. 13 and 14). With the double flowers the calyx is like that of the type. Fimbriation and doubling then appear to be two quite independent variations and fundamentally different, though the inception of both is undoubtedly due to cultivation. Yet another variation was noticed this same year with regard to the scent of the plants, the foliage of some being almost scentless, while in other cases it was distinctly scented, the odour being like that of pine apples. Attention has also been called to this fact by Dr MacWatt, who states that the pine-apple scented form is more robust and sets seed freely, while the scentless form has smaller flowers and does not set seed ~cording to his experience 1. Variation in the direction of greater intensity of flower colour has also been marked in P. malacoides; though the range of variation is not yet so wide as in P. obcbnica., both lilac and deep mauve forms are common, and a deep pink shade was exhibited by Mr James Box in 1914~ ~-. This particular form was further distinguished by its vigorous growth. The plant having "stouter stems, a more robust habit, and flowers twice the size of those of the type." The flowers measured 2"5 cm. in diameter. This giant form appears to be the result of beneficial cultivation l'ather than of any hybridisation, the suggestion that P~'imuia Forbesii may have been accidentally crossed with P.

1 The Garden, January 6, 19121 1~'. 2. u GaTdener's Chronicle, March 14, 1914, p. 180, fig. 82. A~,~,nu~ W. HIr~L 197

malacoides seems no more tenable than. that the deep rose colour of some forms recently exhibited is due to the influence of the pollen of P. roses. According to the editorial note in the Gardeners' Chronicle numerous experiments have been made to cross P. malacoides and P. Forbesii, but no fertile seed has resulted. The most distinct colour form of P. malacoides is that known as "Rose Queen," the flowers of which are of rich rosy colour. A figure of this is given in The Garden of Feb. 27, 1915, p. 104. The variety, was raised by Mrs Denison of Little Gaddesden, Berkhamsted, and is very vigorous in habit with fine trusses of flowers. It differs from other forms chiefly in the breadth of the perianth segments which have become so much broadened that they touch one another and the flower has a rounded outline more like that of a polyanthus.

As in the case of P. obconica, the hybridisation of P. malacoides with other species of Primula has been attempted by many gardeners, but there is no evidence that success has attended any of the experi- ments. The species in a remarkably short space of time has responded to cultural conditions and has sported in the directions of doubling, fimbriation of the corolla segments, albinism, and various colour changes as well as in the direction of increased vegetative vigour. All these ch~mges however must be attributed to the skill of the gardener rather than to the efforts of the hybridiser. P. ~nalacvides has varied under tlfe influence of cultivation in precisely the same manner as have P. sinensis and P. obconica 1, but the time interval required for the disturbance of its equilibrium has been very short. 1 It is of interest that 2. deTzticulata which in 1912 was being grown in large quantities by Messrs Russell at Cedar Nursery, Ham, showed a great range of colour forms, through evmT shade o[ lilac, purple and violet to a distinct bluish shade and also white. The shapeand form of the flowers was also very varied from small with narrow sham'plypointed segments to very large flowers with rounded segments very far removed from the type. Fimbriated flowers were also noticed but no doubling. The leaves were also very diverse in form in some cases being quite coarse. In this species there is no question of any hybridisation having been a~tempted. 198 History of Primula malacoides, Franchet

EXPLANATION OF PLATES.

PLATE XI.

Figs. 1 and 2. Primula malacoides grown at Kew in 1912, very similar to tile plant as originally introduced. Fig. 3. White variety which appeared st Messrs Sutton and Sons in 1912. Fig. 4. A deep colourecl form flowered at Kew in 1914. Figs. 5, 6, 7. Stages in doubling Fig. 7 being a complete double, see Fig. 11, from Messrs Russell in 1912. Fig. 8. An enlarged drawing of the flower seen in Fig. 6, cut open to show the extra segments developed from the connective of the anther. Figs. 9 and 10. Details of the development of the perianth-segments from the connective. Fig~ 11. An enlarged drawing of Fig. 8, the perianth cut open showing a complete inner perianth and further developments commencing from the ~mthers. Fig. 12. An extra segment and anther from the flower represented in Fig. 11. Fig. 13. A large fimbriated flower grown at Kew in 1914 the flower measured 2'35 cm. in diameter. Fig. 14. The calyx of the above magnified showing the toothed margins of the segments. Fig. 15. A flower showing incipient lobes in the sinuses~ The drawings are by Miss hi. Smith.

PLATE XlI. Flowers from a group of seedling plants of.P. malacoides exhibited by l~Iessrs R. L. Russell, Nurserymeu, Richmond, at the Royal Horticultural Society's show, April 9th, 1912. The plants were raised at Cedar Nursery, Ham, and selected from a batch of 15,000 plants. All the flowers are natural size.

Fig. 1. Flowers showing early stages in fimbriation. Figs. 2 and 3. Early stages of doubling with two more or less completely double flowers. Fig. 4. A flower with the segments conspicuously fimbriated. Fig. 5. Three flowers showing an attempt to produce outgrowths from the sinuses. Fig. 6. Three large single flowers measuring 2'2--2'35 cm. in diameter.

Photographed by C. P. Rq[]ill. JOURNAL OF GENETI08, VOL. VII. NO. 8 PLATE Xl dOURNAL OF GENETIO8, VOL. VII. NO. 8 PLATE XII

Fig. 1. Fig. 2.

Fig. 3.

l~'ig. 4.