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Garden and Forest. 



[February 26, 1890. 



Begonia manicata.— -This is a beautiful old species from Bra- 

 zil, and, under liberal treatment, one of the most useful in cul- 

 tivation. It is of moderately free growth, and forms a neat 

 specimen when young. The short, fleshy stems are well 

 clothed with large, oblique leaves of a glossy green color, the 

 footstalks of which are encircled, irregularly, by little hairy 

 scales of a bright reddish color ; similar scales appear also on 

 the veins that prominently mark the under side of the leaves, 

 and sometimes on the flower-stalk. The pale pink flowers are 

 small, but very freely borne in erect and large branching pan- 

 icles ; they are exceedingly decorative, and continue in full 

 beauty for a considerable period. The plant may be readily 

 propagated from cuttings — inserted in sandy soil, and placed 

 where they may obtain a moderate amount of bottom-heat, 

 with shade from sunshine till rooted — at any season. During 

 summer they should be shaded from bright sunshine, and 

 kept near the glass, in a house that affords an intermediate 

 temperature, with a moist atmosphere ; in winter shading will 

 be unnecessary, and, as that is the flowering season, a some- 

 what drier atmosphere will then be requisite. The flowering 

 season may be prolonged by the administration of weak 

 liquid manure occasionally. When this season has passed 

 the plants should be cut back slightly, just sufficient to keep 

 them in proper shape, as they are liable to assume a disor- 

 derly appearance as they grow old, rested for a brief period, 

 and then repotted. 



Habrothamnus elegans. — Ever since its introduction, some 

 fifty years ago, this plant has enjoyed the greatest popularity 

 among the owners of greenhouses in Europe. In this coun- 

 try it is, unfortunately, not quite so popular, but few who see 

 it well grown will rest contented until it has been added to 

 their collections. To see the plant in all its gracefulness and 

 beauty, and to understand that such perfection in culture can 

 be attained with the greatest ease, by no means conveys a 

 complete idea of its meritorious character. Add to these quali- 

 ties the fact that its beauty continues throughout the entire 

 year, and is most intense during the dull periods of winter 

 and spring ; add further the fact that it requires only enough 

 artificial heat to exclude frost, and you will have gained a 

 fair estimate of its utility. It is, in this climate, essentially a 

 greenhouse plant, but it is not at all tender. In its native 

 country of Mexico it grows at an altitude of 4,000 feet, and that 

 fact indicates its comparative hardiness. It is a rather tall- 

 growing shrub, of somewhat slender growth, with dark green, 

 ovate-lanceolate, alternate leaves. The younger branches and 

 the under side of the leaves are pubescent. The tubular flow- 

 ers, about an inch in length and of a reddish purple color, 

 are freely produced in dense terminal cymes. When the 

 flowers are artificially fertilized, they are succeeded by bril- 

 liant red berries, that lend the plant an additional charm. It 

 is seen at its best when planted in a border and trained on a 

 pillar, trellis or the back wall of a lean-to house ; in such posi- 

 tions it grows and blooms continuously. When grown in pots 

 it should have abundance of root-room, and an occasional 

 application of liquid manure helps it materially. As the 

 flowering shoots proceed from the previous season's wood, 

 some special care must be exercised in the matter of pruning; 

 these operations, however, are necessary only when the growth 

 becomes too dense or when the plant gets beyond its proper 

 limits. Cuttings, made from firm young shoots, produce 

 roots very readily when inserted in sandy soil during spring or 

 summer, and kept shaded for a few days. Under the more re- 

 cent name of Cestram elegans this plant is now known to many. 



Botanic Gardens, Cambridge, Mass. M. Barker. 



Correspondence. 



A So-called "Poisonous" Primrose. 

 To the Editor of Garden and Forest : 



Sir. — The literature of the alleged poisonous character of 

 the Primula obconica commences in Garden and Forest. In 

 its issue for May 2d, 1888, Doctor James C. White, of the 

 Harvard Medical School and a specialist in skin diseases, 

 states that he was consulted "by one of our largest dealers 

 in flowers, for an inflammation of the skin of the hands and 

 face. The appearance which these parts presented indicated 

 a dermatitis venenata of an eczematous type." The florist at- 

 tributed his trouble to some plant that he had been handling, 

 and suspicion fell upon an Acacia pubescens and Primula 

 obconica. Some of the florist's assistants were attacked in a 

 similar manner. This skin trouble did not appear until after 

 the plants were brought into the shop and were handled in 

 large quantities. To confirm his suspicions, Doctor White 

 wrote to Professor Goodale, of Harvard, asking if he had ever 



known this Acacia or this Primula to cause skin troubles. 

 Professor Goodale referred the matter to the gardeners at the 

 Botanic Garden, and replied: "Our gardeners say that they have 

 not experienced any trouble from A. pubescens or P. obconica, 

 but that there is a plant, as yet undetected, which has lately 

 given them a good deal of irritation." Early the following year 

 Dr. White returns to the subject, and in Garden and Forest 

 of February 20th, 1889, page 94, after referring to the issue of 

 the previous year, he says : " The florist and some of his as- 

 sistants, whose skin disturbance, therein (last year) described, 

 dermatitis venenata, subsided in a short time, and the skin of 

 the three affected persons has remained in a healthy condition 

 until recently. Within the last two or three weeks, however, 

 they have all manifested a recurrence of the same symptoms 

 in about the same degree as last year." Primula obconica, one 

 of the suspects of the former year, they now feel assured is 

 the cause of the trouble, as this did not manifest itself until 

 this plant came into the store for sale and had been freely 

 handled in making up floral decorations. 



The next evidence comes from Joseph Meehan, of German- 

 town, Pennsylvania. In Garden and Forest for March 27th, 

 1889, Mr. Meehan quotes from a letter of David Cliffe, who, 

 after potting a lot of Primula obconica, had his face so swollen 

 that he remained completely blind for a day. This was the 

 severest case yet reported ; but it should be stated that Mr. 

 Cliffe was at that time suffering from poisoning by Euphorbia 

 (Poinsettia) pulcherrima. Mr. Meehan states that he himself 

 is obliged to avoid contact with Poison Ivy (Rhus Toxico- 

 dendron), and that the seeds of Oregon Maple (Acer macro- 

 phyllum) and of Hop Hornbean (Ostrya Virginica) excite 

 itching and inflammation of his hands, while many others who 

 have handled them are not at all affected. These seeds, he 

 states, "are both covered with minute hairs." On June 12th, 

 1889, Garden and Forest published a note from Mr. John N. 

 Gerard, of Elizabeth, New Jersey, in which he gives the testi- 

 mony of a lady who, with several daughters, had experienced 

 most serious inconvenience from handling Primula obconica' 



English gardeners, as a rule, do not appear to be so sus- 

 ceptible to the irritation caused by Primula obconica as do our 

 own, o'r it may be that the plant grown in the humid climate of 

 Great Britain has its irritating properties less conspicuously 

 developed than in this country. 



It is certainly singular that so many should have suspected 

 Primula obconica as the cause of annoying skin troubles in 

 themselves and others, without closely examining the plant. 

 A pocket magnifier of moderate power would have revealed 

 such a condition of hairiness that would have suggested 

 further examination with a compound microscope. Both 

 surfaces of the leaves, and especially their margins, show a 

 great abundance and variety of hairs, while the petioles or 

 leaf-stalks are conspicuously hairy, as may be seen without 

 the aid of a glass. To one interested in Trichomes, this plant 

 presents material for study in great abundance and variety. 



Fig. 23. — Magnified leaf-hairs of Primula obconica. 



At my request, Mr. John Payne has made a drawing of a 

 fragment of a leaf as it appears under a microscope. This 

 shows the hairs which fringe the margins of the leaves and 

 the calyx-lobes. The large projection in the engraving is 

 one of the teeth upon the margin of the leaf. The surface of 

 a leaf shows some hair like those on the margin, others much 

 shorter and some much longer and weaker. The hairs upon 

 the petioles, so long as to give them a shaggy appearance, 

 present, under the microscope, a great variety in appearance. 

 The hairs are seen to be made of many cells placed end to 

 end. These cells are oblong in outline and diminish slightly 

 in size from the base upward. Frequently one of these cells 

 is much narrower than the one above and the one below it, 

 appearing like a mere stem connecting two parts of the hair. 

 This occurs in no particular portion of the hair, and some- 

 times there are two constrictions of this kind in the same 

 hair. In many plants the cells have a deposit of silex. This 



