AN ENCYCLOPEDIA OF HORTICULTURE. 



Orchidese continued. 



mascula, Morio, militaris, maculata, &c.). Salop con- 

 tains, in a small volume, an abundance of nutritive starch, 

 associated with a peculiar gum, analogous to Bassorine ; it 

 was formerly considered a powerful analeptic; it is now 

 used as a sweet, scented jelly, or mixed with chocolate. 

 The root of Helleborine (Epipactis latifolia) is employed 

 for arthritic pains ; those of Himantoglossum hircinum, 

 Spiranthes autumnalis, and Platanthera bifolia, are 

 reputed to be aphrodisiac. The flowers of Gymnadenia 

 conopsea are administered for dysentery ; and, in North 

 America, the tubers of Arethusa bulbosa are used to 

 fctimulate indolent tumours, and in toothache. The root 

 of Spiranthes diuretica is renowned in Chili. The rhizome 

 of Cypripedium pubescens replaces the Valerian as an 

 untispasmodic, in the estimation of the Anglo-Americans" 

 (Decaisne and Le Maout). 



ORCHID FERTILISATION. The great source 

 cf information on this, as on so many other important 

 and interesting questions in Natural Science, is to be 

 found in the writings of Charles Darwin, who has written, 

 upon this subject, the well-known work " On the Various 

 Contrivances by which British and Foreign Orchids are 

 Fertilised by Insects." This book must always be re- 

 ferred to by those who wish to understand the very 

 curious structures that adapt many Orchids, in a very 

 peculiar degree, to benefit by the visits of insects, while 

 a smaller number are adapted for self-fertilisation alone. 

 Not a little information is contained also in the works 

 of Dr. Hermann Miiller (of the chief of which a trans- 

 lation has been published, entitled " The Fertilisation of 

 Flowers "), of Professor Asa Gray, of Delpino, and of 

 many others, whom it is impossible here even to enu- 

 merate. 



An endeavour will be made here to bring together some 

 of the more interesting results arrived at by the various 

 writers, [selecting a few of the more characteristic 

 examples from the species native in Britain, and there- 

 after giving a short account of some exotic species that 

 exhibit peculiarities not met with in British Orchids. 

 The flowers of Orchids in general are very curious in 

 form and arrangements of their parts. This is well seen in 

 the many figures of Orchids that have appeared in this 

 dictionary (see Aceras, Aerides, Calaiithe, Cattleya, 

 Chysis, Coelogyne, Cymbidium, Cypripedium, 

 Dendrobium, Epidendruin, Masdevallia, Maxil- 

 laria, and Miltonia). 



But, despite this diversity, it is never difficult to 

 recognise, that each flower is supported on a stalk, 

 twisted half round, and that, when cut across, there are 

 very many ovules visible in the stalk, and that this 

 part really encloses the ovary, which is, therefore, in- 

 ferior, and consists of three carpels, joined usually along 

 their edges only. The flowers show six parts externally, 

 viz., three sepals, much alike, and three petals, of which 

 the lower one, in the mature flower, is almost always 

 larger, broader, and more handsomely coloured than the 

 others, and is called the labellum. It is often peculiar 

 in form also, and very frequently it ends in a spur, 

 which projects backwards, as the nectary. This latter, 

 frequently, does not exude nectar into the tube, but 

 contains it in the thin cells lining the latter ; the walls 

 of these cells are so thin as to allow insects (even 

 moths) to pierce them readily, so as to obtain the juice. 

 The tube is often nearly absent, but it is often of great 

 length, and permits the honey to be secured only by 

 insects with long probosces (such as some moths and 

 butterflies possess), or by boring holes from without, 

 as humble bees often do. This latter method, of 

 course, does not benefit the flower at all. The essen- 

 tial, or reproductive, organs in the flower, consist of 

 the stigmas and the fertile stamen, or, in Cypripediece, 

 the two fertile stamens, and the remains of two stamens, 

 or of one stamen reduced to the state of a staminode, 



515 



Orchid Fertilisation continued. 



i.e., of a stamen no longer of use in forming pollen, but- 

 modified to perform some other function for the welfare 

 of the plant. The relation of the larger parts of the- 

 flower to one another, will be more easily understood 



FIG. 762. FLOWER OP L^ELIA ALBIDA. 



from the accompanying woodcnt of the flower of Lcelia 

 albida (see Fig. 762). The sepals are the three narrower 

 parts, situated behind, and overlapped by, the three 

 petals, of which the lower in the figure is the labellum 

 or lip. The dark, central spot is the opening of tho 

 nectary ; and the upper part of the spot, is the situation 

 of the stigmas. In Orchids, only two of the three are 

 developed as stigmas, and often in fact, usually they 

 unite. Just above the dark spot is seen the column, 

 united to the labellum by two ridges. This column ia 

 regarded as formed by the fusion into one body of the 

 upper part of the carpels, the fertile stamens, whether 

 one or (in Cypripedium) two, and probably three or (in 

 Cypripedium) two undeveloped stamens ; but of the latter, 

 as a rule, no clear trace remains. At the tip of the 

 column is a body the rostellum usually regarded as 

 the third stigma become useless as a stigma, but of 

 great importance in securing the conveyance of pollen 

 from one flower to the stigma of another. The labellum 

 is also believed to be of compound nature, and to bo- 

 formed of two metamorphosed stamens, and the median 

 petal, closely united in growth. 



The structure of the fertile stamen, and the process 

 by which pollen is conveyed from it to the stigma 

 of another flower, by insect aid, in a common British 

 Orchid will next be described, selecting, as a wide- 

 spread and easily-obtained plant, the Spotted Orchis 

 (Orchis maculata). In this species, the perfect stamen 

 is situated on the front of the column ; and in the anther 

 there are two pouches, in which the pollen grains are 

 inclosed. The grains are joined together into small masses, 

 and these, again, are joined to form a single mass 

 (pollinium) in each chamber. Each pollinium is formed 

 like a club, supported on a slender stalk (caudicle), 

 which ends below in a round, sticky ball. The two- 



