756 



THE GARDENERS 



CHRONICLE. 



[Nov. 17, 1855. 



being a forked one, I took one part off, and cut it up 

 indiscriminately into 20 small pieces, about the size of 

 horse Beans ; I planted each piece in a 3-inch pot, 

 placed them in a little heat, and every one grew. 



* Early in the spring of 1855 the two old plants or 

 tubers were placed in a little heat, where they soon 

 pushed three or four strong shoots, which I reduced to 

 one to each plant ; the shoots taken off I struck as 

 cuttings. During the winter of 1854 and 1855 young 

 tubers or seeds of this Dioscorea were received and 

 grown in the propagating house. In March they 

 were nice plants in 8-inch pots. I put them with the 

 two old plants and kept them growing slowly on in a 

 temperature (by night) just sufficient to keep frost out. 

 Several of the last-named plants, and likewise some of 

 those I raised from cuttings, were distributed to Fellows 

 of the Society. The others that remained, and the two 

 old plants, were planted out, at the foot of a Vine border 

 the first week in June, 1855. The soil in which they 

 were planted was dug a spit and a half deep and 

 mixed with a good dressing of leafmould and peat. 

 Each plant was covered with a hand glass, except those 

 struck from pieces of old tubers, which were planted 

 four under a glass ; the glasses were kept on all the 

 season, but were tilted up on the north side from the 

 first week after planting out. Out of nine of the plants 

 raised in the propagating house four or five of them 

 never made a leaf after being planted out (which I can 

 account for in no other way than that the young tubers 

 had reached the bottom of their pots, and had turned 

 again when I planted them out). Notwithstanding this, 

 however, their tubers continued to increase in size. 

 The other four produced good sized tubers, the 

 heaviest of which weighed 11 oz. The two old 

 plants grew very fast, and I trained the stems both 

 inside and outside the glasses {i.e., pegged them down) 

 and covered the axil of each leaf with leaf-mould. 

 When I took them up I found that tubers had formed 

 at the axils of the leaves, where the shoots had been 

 pegged down ; varying in size from 2 to 6 inches in 

 length. At each of the old plants there were also two 

 or three large tubers, which had gone straight down to 

 the bottom of the border, and then turned under the 

 drainage of the Vines. Out of eight of the young 

 plants propagated from pieces of old tuber, four of 

 them likewise sent down tubers to the bottom of the 

 border ; but they were very slender, the heaviest of 

 them did not weigh more than 4 oz. It may be worth 

 mentioning that where the first Dioscorea was planted out 

 in 1854, a piece of the tuber was left in the ground, 

 at a depth of 1 8 inches, and that it sent up a stem this 

 summer ; this I uncovered to the bottom, and I found 

 that the new tuber commences to form at the top of the 

 old one, and grows downwards ; for to the depth of the 

 old tuber there was nothing but stem. 



n In the cultivation of this Yam we should therefore 

 apparently plant shallow on a deep heavy soil, trenched 

 some months beforehand. We should also force less 

 and plant much earlier in the season. This last point, 

 however, I expect must be determined by experience. I 

 may add that on stems not pegged down little bulbs had 

 formed at the axils of the leaves about the size of Peas." 



The inference we draw from these explicit rela- 

 tions of two experiments tried by competent persons 

 is undoubtedly in favour of the climate of England 

 being good enough for the Chinese Yam. Nor is 

 our opinion at all altered by the knowledge that 

 many have wholly failed in growing it, a circum- 

 stance sufficiently explained by the badness of the 

 sets which were planted, or by mistakes as to the 

 way in which the crop requires to be managed. 



Those who are desirous of seeing the roots pro- 

 duced under the circumstances here explained, will 

 have the opportunity of doing so at the autumn 

 meeting of the Horticultural Society on Tuesday 

 next in Regent Street. 



It will have been remarked that the question of 

 the comparative value of the Quercus sessiliflora 

 and Quercus pedunculated has once more been raised 

 by some of our correspondents. Certainly there is 

 no inquiry whatever of greater national importance, 

 affecting as it does the value of the staple produce 

 of our Enelish forests. Nevertheless it is 



thought that all Oaks with stalkless acorns belong 

 to Q. sessiliflora, whereas Q. pedunculate itself has 

 sometimes its acorns in the same state. The true 

 character of Q. sessiliflora is to have long-stalked 

 leaves and short-stalked or stalkless acorns. On 

 the other hand Q. pcdunculata has short-stalked or 

 stalkless leaves, and long-stalked acorns. It is in- 

 deed in the leaves that the means of distinguishing 

 the two kinds exists, even better than in the acorns. 

 Those of Q. sessiliflora have always long yellow 

 stalks, while the leaves of Q. pcdunculata either 

 have no stalks at all, or if there be stalks they are 

 either green or red. The timber of the first, which 

 has very uniform and fine medullary rays, is called 

 Chesnut by uninformed persons ; that of the second, 

 which has many very large medullary rays, mixed 

 with the smaller ones, is the common Oak of the 



timber merchants. 



It is time that this question should be finally 

 settled, and we earnestly invite the co-operation of 

 our numerous readers in bringing it to issue. The 

 inquiry is of rather more importance than the 

 proper form of a Tulip, or even than the quality of 

 a Plum ; and should engage the earnest attention 

 of country gentlemen, through whom alone the 

 truth can be ascertained. We earnestly invite 

 their communications wherever they have certain 

 personal knowledge of the real facts of the case. 



one 



regarding which our supineness is unparalleled. Is it 

 not possible to prove, by irresistible evidence, the 

 respective qualities of these our two British Oaks ? 

 and to set at rest the conflicting testimony, if that, 

 indeed, can be called testimony which is for the 

 most part hearsay, or mere tradition — in a matter 

 which most seriously concerns the landed property 

 of these kingdoms. 



According to A, our valuable Oak is all produced 

 by Quercus pcdunculata. According to B, the finest 

 Oak is, or was, that of Quercus sessiliflora* B asserts 

 that the latter grows much faster and forms a finer 

 tree than the former; but A, while admitting the 

 fact, replies that the badness of its quality renders 

 its rate of growth unimportant. 



Our columns have from the very establishment of 

 the Gardeners' Chronicle been open to this inquiry, 

 and contain numerous statements and counter- 

 statements, out of which it seems impossible to 

 mlect the truth. These discrepancies probably 

 arise in some cases from the real distinctions be- 

 tween the two Oaks being misunderstood, Jt U 



New Plants. 



148. Dendrobium cumulatum. 



D. cumulatum (Stachyobium) racemis densis lateralibus, petalis 

 obovatis obtusis sepalis multb raajoribus, raento sepalis sequali 

 angusto incurvo acutiueculo labelli glabri ungue lineari pone 

 basin unidentato lamina oblonga obtuea. 



A most beautiful addition to our collections. We 

 first received a specimen in September last from Mr. 

 Charles Junkermann, who found it growing in the 

 garden of Mr. F. Coventry, of Shirley, near Southamp- 

 ton, and who describes the plant as having a dark stem 

 covered here and there with Vanilla- scented blossoms. 

 Since that time we have also had it from Mr. C. B. 

 Warner. It appears to have been bought at one of Mr. 

 Skinners sales ; but its real history is unknown to us. 



The flowers are nearly 2 inches long, with the delicate 

 pink colour and transparent texture for which Dendrobium 

 transparens is so remarkable. They grow in lateral 

 compact clusters, five or six together, in the same 

 manner as in D. aduncum. The depth of colour in 

 them varies ; Mr. Warner's specimeus having been very 

 much darker than those from Mr. Coventry, and more- 

 over having the delicate lip itself freckled with rose- 

 colour. The leaves have not been seen by us. The species 

 must stand next D. aduncum, from which it differs in its 

 large flowers, incurved acute chin, and perfectly hair- 

 less obtuse lip. There is more than one nearly allied 

 unpublished species in our possession from Java, whence 

 this perhaps has come. 



149. RoNDELETIA ANdMAUU 



R. anomala; viridi-pubescens, foliis ovatis acuminatis breviter 

 petiolatis, glandulis quibusdam stipularum locr>, capitulis 

 terminalibus trifloris, calycis laciniis linearibus foliaceis glan- 

 dulis interjectis, coroilse tubo dupto longiore filiformi limbo 

 5-partito reflexo laciniis retusis : faucis annulo lineari intus 

 villoao. 



A beautiful Guatemala hothouse shrub, lately raised 

 from seeds by the Horticultural Society, to which they 

 had been presented by its generous and indefatigable 

 correspondent G. U. Skinner, Esq. The plant has 

 something the appearance of a Bouvardia ; the flowers 

 are of the richest vermilion red, with a yellow eye, about 

 the size and form of R. odorata, but with the orifice of 

 the tube closed by yellow hairs. What is very remark- 

 able this shrub has no stipules, instead of which there 

 is a line of minute shining glands, others like which also 

 appear about three together, between the leafy lobes of 

 the calyx. Flowering in November this plant must be 

 regarded as one of the most brilliant species which even 

 Mr. Skinner has been able to add to our gardens. 



VEGETABLE PATHOLOGY.— No. XCV. 



379. Exostosis.* (Knaurs.) The Beech, Hornbeam, 

 Sycamore, Oak, Hawthorn, and some other trees are 

 subject to a very curious affection, indicated by the 

 production of hard lumps of wood entirely disconnected 

 with the common central column, surrounded by the 

 bark, and causing it to project more or less decidedly, 

 according to their size. They vary from the size of a Pea 

 to some inches in diameter, and are remarkable for the 

 wavy lines with which their surface everywhere is marked. 

 The origin of these bodies was very obscure till Trecul 

 studied them, and it is to his memoir in the 20th 

 volume of the third series of the u Annales des Sciences 

 Naturelles" that we are indebted for the following in- 

 formation. It does not appear that they are due to the 

 puncture of an insect, but they seem to arise from 

 some peculiar constitutional condition of the particular 

 plant on which they are formed. 



380. In order to ascertain the origin of these bodies 

 it is necessary to examine them in a very early stage 

 of growth. At a later period the traces of their 

 primary condition and their relation to the wood are in 

 general so masked as to make it almost impossible to arrive 

 at any satisfactory conclusion. It will be seen as we 

 proceed that Dutrochet's theory that Knaurs are from 



* t&j-Taia-K;, projection of bones as of the cheek bone, TriJcnl 



considers i; a sort of ligneous bvpertropby. 



the first altogether independent of the part of the tree 

 on which they grow without any terminal bud, tiat 

 they are in fact mere latent embryos and not true buds 

 at all, is perfectly untenable. The important bearing f 

 the case on the theory of the formation of wood from 

 tissue descending from the buds, will not escape 

 the notice of any well instructed botanist, though 

 it has little connection with our present subject. Now 

 in every case where a sufficiently young Knaur is under 

 observation, there is no difficulty in ascertaining the 

 presence of a terminal bud, which is always at some 

 early period of growth connected by a fibro- vascular 

 system with the woody axis upon which it ig 

 seated. It is far more easy to ascertain this con- 

 nection in the Hornbeam than in the Beech, because 

 traces of the original formation remain a longer time, 

 and in fact are seldom entirely obliterated. Little 

 buds in the former case may be seen to creep on 

 the surface of the bark, assuming a very peculiar 

 form which may be compared with the shoot of some 

 Jungermannia, or a crawling scaly Annelid. They 

 are sometimes very small, not exceeding § of an inch 

 in length, and a sixth of these dimensions in breadth, 

 composed of two ranks of little imbricated scales sepa- 

 rated by a longitudinal furrow. Though of such small 

 dimensions they are often of considerable age ; and if 

 they are carefully removed so as to take with them a 

 few layers of bark, their point of origin will be found 

 not to correspond with the apparent point of attachment 

 to the bark, that is with that of the scales which are 

 furthest from the top of the bud, but immediately below 

 the summit itself, or the youngest scales, so that the 

 buds only apparently creep over the surface of the 

 bark. The scales, in fact, as fast as they are formed 

 are pushed backwards, together with the thin bark to 

 which they are attached. And as this rejection of the 

 old scales cannot take place without the rupture of the 

 tissues of the bark, though they were at first disposed 

 all round the bud they are thrust back on the side oppo- 

 site to the rupture, and thus a furrow is formed which 

 runs through the whole series of scales. Occasionally the 

 scales are thrown back on two sides of the bud, and 

 then they form two series, making a more or less acute 

 angle with each other. Sometimes these buds are 

 attached immediately to the wood itself which is more 

 prominent at the point of attachment, a method of which 

 we shall have more to say in the next article, but in other 

 instances the wood itself of the bud increases so as to 

 form within the bark a distinct nodule, which at la&t 

 loses all attachment, and appears under the guise 

 of a true Knaur. As it increases, a considerable 

 pressure is exercised on the bark, which in turn as it 

 increases in thickness lifts up the nodule, and finally 

 ruptures the fibro- vascular bundle by which it was 

 attached, so as to leave it quite free. It no longer 

 depends upon any nutritive matter derived from the 

 growing surface of the axis, but it has its own system of 

 bark and wood, and receives all its nutriment from the 

 bark in which it is enveloped, and that already elaborated. 

 It has no need therefore, like a parasite, of any system 

 by which the juices it receives may be elaborated, and 

 in consequence the bud to which it owed its first 

 origin may become entirely abortive without any detri- 

 ment to the growth, and thus all trace be lost of it& 

 ancient connection with the axis, or of the bud to 

 which it owed its first origin. In Paulownia imperials, 

 M. Trecul has observed a Knaur supported by two 

 peduncles, as if it had arisen from the union of two buds. 



381. After a time the bark which covers the Knaurs- 

 is apt to decay, and if the injury extends down to the 

 nodule itself, its further development must be confined 

 to the side nearest to the axis. The decay may be cob- 

 tinued to such an extent as to leave merely a ring ot 

 wood instead of a globose nodule. The Knaurs occa- 

 sionally, though freely developed above, adhere per- 

 manently by a strong peduncle to the wood. 



382. Though the bud for the most part decays, this is 

 not universally the case, nor does it always remain in fr 

 rudimentary state. Dr. Lindley has figured a branch 

 springing from a Poplar Knaur in his u Theory o 

 Horticulture." A less marked instance is illustrated by 

 Trecul, though of considerable interest, inasmuch as W 

 bud which had been for years semi-dormant has a. 

 length assumed a more active vitality, and has in i con- 

 sequence been more perfectly developed. In the UU> r 

 Knaurs are so prone to develope their buds that t <7 

 are used for propagation under the name of uovolt- 

 clavus of the Olive mentioned by Re is probably tn 

 same thing. Mr. Lowe has f at my request, ift W» 

 inquired after such an affection at Madeira, so that 

 should seem to be local. Neither could he hear slo- 

 thing of the callosities on the roots described by ^ 

 same author, Molina says that they do not occur 

 Chili. M. J. B. 



WASP PAPER. 



It is well known that wasps and hornets make the£ 

 combs and the outer covering of their nests of a s » 

 hire called by the name of wasp or hornet paper, qu 

 different from that which bees make use of. f 10 ".^ 

 of your readers who are less familiar with this sii»J > 

 the following observations on the nature of thesubsta 

 which goes by this name may not be without interes ■• ^ 



I may premise that a wasp's nest is made of a c 

 of paper of this kind, inside which the comb is fasten 

 horizontally in stages, not vertically like bees co • 



and the mwer are nung successively uuo **«*-- 



to the number of five or more. The ceils are hex V 



