434 



Garden and Forest. 



[Number 401. 



condition, scantily supplied with water and kept in a low 

 temperature, usually resist all attempts to produce spot 

 artificially." 



Orchids generally fall a prey to spot in winter and early 

 spring. If the temperatures of the houses are higher than 

 they ought to be at these seasons spot is almost certain to 

 appear upon such plants as Phala2nopsis,Vanda, Aerides,Den- 

 drobium, and almost always upon the young leaves. Care- 

 lessness in stoking or ventilating or copious damping down 

 in damp cold weather are the chief causes of spot at these 

 times, as every experienced cultivator knows. What we 

 did not know, however, previous to these investigations 

 was whether the disease itself was infectious and grew 

 from a very small beginning in spite of all the cultivator 

 could do, and whether, as some held, when once spot 

 attacked a plant it was next to impossible to save it. I am 

 not quite satisfied that the particular form of disease inves- 

 tigated by IMr. iVIassee is the only one that affects Orchids, 

 and which falls under the same designation. There is a 

 spot-like disease which attacks the stems more than the 

 leaves, and which may often be traced from the base 

 upward. There is also that "galloping consumption " into 

 which Cattleyas of the character of C. Dowiana and C. 

 Hardyana fall, changing within a week from apparently 

 quite healthy plants into black watery masses as though 

 they had been boiled. I suppose Mr. Massee will say that 

 the ordinary spot which attacks Orchids, like influenza 

 which attacks mankind, is not the only form of disease 

 which may spring from a chill. Cultivators generally will 

 be grateful to him for clearing away the doubt and mys- 

 tery in which Orchid spot had become wrapped. We 

 know where we are now, at any rate. 



Mr. Massee summarizes his observations as foUovi's : 

 The Orchid disease known as spot is of non- parasitic 

 origin, the initial cause being the presence of minute drops 

 of water on the surface of the leaves at a time when the 

 temperature is exceptionally low and the roots copiously 

 supplied with water. 



The effect of the chill produced by the drops of water 

 under the above-mentioned conditions is to cause plasmo- 

 lysis of the cells of the leaf underlying the drops ; this is 

 followed by the precipitation of tannin and other sub- 

 stances, and eventually the complete disintegration of the 

 cells. 



Spot, in the broadest sense of the term, which would 

 include the effects of exceptional meteoric conditions on 

 the living parts of plants, more especially the leaves, when 

 growing in a state of nature, is, in the case of cultivated 

 Orchids, mainly, if not entirely, caused by the three fol- 

 lowing conditions: (i) too high a temperature; (2) too 

 much water, and not sufficient air in contact with the 

 roots; (3) watering or spraying with a falling, instead of 

 a rising, temperature. 



The paper is illustrated by colored figures of the leaf of 

 Eria rosea and Bulbophyllum Careyanum, showing the 

 cells and their contents and the process of development of 

 the disease. ,„ „. , 



London. W- WatSOIl. 



New or Little-known Plants. 



Kalmia cuneata. 



THIS is -probably one of the rarest plants in eastern 

 America, and there is no record that any botanist has 

 seen it alive since Nuttall's time until two years ago. It 

 was discovered in Carolina by the French botanist Michaux, 

 who left few plants undiscovered in the region which he 

 explored, and was described in his Flora Boreali- Americana. 

 A flower and a leaf of Michaux's specimen are preserved in 

 the Gray Herbarium. In the Herbarium of the Philadel- 

 phia Academy of Sciences are two specimens in fruit 

 labeled by Nuttall and collected in South Carolina. The 

 labels give neither date of collection, exact locality, nor the 

 name of the collector. Taken late in the autumn, these 

 specimens show, as Nuttall states in his Genera of North 



American Plants, that the leaves of this species are decidu- 

 ous, a fact which every other writer on the genus since 

 Nuttall has overlooked. Nothing more was seen of Kalmia 

 cuneata until the winter of 1893-94, when it was found by 

 Mr. W. W. Ashe, of the Geological Survey of North Caro- 

 lina, who detected it in a Pine-barren swamp between the 

 Cape Fear and Black rivers, Bladen County, North Carolina, 

 about ten miles north-east of Whitehall, a small village on 

 the Cape Fear River. 



Kalmia cuneata (see illustration on page 435 of this 

 issue) is a shrub with slender straggling stems, from two 

 to three feet tall. When they first appear the branchlets are 

 bright red or green tinged with red, and are glandular- 

 pubescent ; during their first winter they are dark red- 

 brown and slightly puberulous, growing glabrous and 

 darker-colored in their second year. The terminal buds 

 are linear-lanceolate, very acute, covered with loosely 

 imbricated dark red scales nearly a quarter of an inch long, 

 and are more than twice as long as the ovate-acute lateral 

 buds. The leaves are alternate, clustered at the ends of 

 the branches, entire, oblong-obovate, gradually narrowed 

 at the base, narrowed and acute or rarely rounded at the apex, 

 which is usually furnished with a minute mucro, sessile or 

 short-petiolate, and deciduous ; they are thin, dark green on 

 the upper surface, pale yellow-green and pilose, with short 

 white hairs on the lower surface, from three-quarters of an 

 inch to an inch and a half long and from a quarter to a 

 third of an inch wide, with stout yellow midribs and ob- 

 scure primary veins arcuate within the slightly thickened 

 revolute margins, and reticulate veinlets. The flowers, 

 which appear in June, are borne on slender drooping pedi- 

 cels often nearly an inch in length and covered with scat- 

 tered glandular hairs, and are produced in few-flowered 

 umbels from buds formed in the axils of the two or three 

 upper leaves of the previous year, and are thus crowded at 

 the base of the shoot of the season. The calyx is orange- 

 green and persistent under the fruit, with ovate-acute lobes. 

 The corolla is slightly folded, light green and puberulous 

 in the bud, and after expansion is from one-half to three- 

 quarters of an inch across, slightly lobed, creamy white, and 

 marked at the base of the limb with a broad light red band. 

 The capsules are slightly roughened, about an eighth of an 

 inch in diameter, and are borne on long slender drooping 

 stems. In the swamp on the Cape Fear River, Kalmia 

 cuneata grows in sterile sandy, and often submerged, soil, 

 associated with Cassandra calyculata, Andromeda speciosa, 

 Myrica cerifera, Ilex glabra. Ilex lucida, Cyrilla racemiflora 

 and Pinus serotina. During the summer of 1894 it was 

 introduced into Mr. George W. Vanderbilt's Arboretum at 

 Biltmore, North Carolina, where it flowered in June of the 

 present year. For the specimens which Mr. Faxon has 

 figured in our illustration we are indebted to Mr. C. D. 

 Beadle, of the Biltmore Arboretum. The flowering branch 

 is from a plant cultivated at Biltmore. C. S. S. 



Plant Notes. 



QuERCUs cocciNEA. — The Scarlet Oak always comes into 

 mind with the thought of the splendors of our autumn 

 forests. No other American tree flames into more brilliant 

 color or retains it longer than this Oak, which often is in full 

 glow after the leaves of its companions have fallen, and 

 not infrequently its scarlet tints are retained until the 

 ground is white with snovi'. The tree, however, is beau- 

 tiful at all seasons of the year. At its best it is seventy or 

 eighty feet high, with a trunk two or three feet through, 

 comparatively small branches and a somewhat open head, 

 so that it has not the appearance of rugged strength which 

 characterizes some other Oaks. It has a certain grace of 

 outline, however, and its thin glossy leaves and dark smooth 

 bark are distinct and attractive. It is not so commonly 

 planted in pleasure-grounds as the Pin Oak or the Red 

 Oak, but it can be moved without difficulty ; it will grow 

 rapidly on thin light soil, and it makes an admirable 

 street tree. 



