113 



ORCHIDACE^E. 



ORCHIS. 



Ill 



other and to the exterior pieces. It is only a few of their modifica- 

 tions which it seems important to notice. The lateral pieces are 

 occasionally bifid, as in certain species of Habenaria : in Megaclinium 

 falcatum they are glandular at the apex; in most cases they are 

 distinct from the column ; but in Lepanthes, Gongora, Disa, and some 

 others, they are adnate to that organ ; in no instance are they spurred 

 or saccate. The lip is either distinct from the column or united to it, 

 stalked at its base, or dilated there, and often extended into a bag or 

 spur, which is sometimes, as in certain species of the genus Epiden- 

 drum, consolidated with the ovary ; very rarely it has two spurs, as 

 in Diplocentrum. In the instances of Camarotit and Acropera it is 

 saccate at the point Its form is infinitely varied, the extremes of 

 variation being Paxtonia for simplicity, and Coryanthes or Stanhopea 

 for complexity. These and all other complicated forms may, without 

 difficulty, be reduced to a 3-lobed type, the simple form of which is 

 found in Maxittaria, Bletia, and many Cattleyas. The lip is often so 

 slightly articulated with the column as to swing to and fro upon the 

 least disturbance, on which account it sometimes seems as if it were 

 endowed with a power of spontaneous motion : this is particularly 

 apparent in certain species of Pterostytit. There is a frequent 

 tendency in the lip to produce tubercles or lamella; upon its surface ; 

 the latter are always confined to the veins, the former are principally 

 found near the base of the lip, and do not appear to have any relation 

 to the veins : it is in the genus Onddivm, Eria, and Zygopetalnm that 

 these bodies, the use of which is unknown, are most conspicuous. 

 Not unfrequently the lip is hairy, convex, and so marked and coloured 

 as to bear no little resemblance to nn insect. 



It is usual to call the exterior series of floral envelopes calyx, and 

 the interior corolla ; but the analogy of Marantacece renders it probable 

 that the so-called petals are a row of outer sterile stamens. This 

 however is a point upon which it is not here necessary to enlarge. 



The centre of the flower is occupied by a body called the column, 

 which is formed by the consolidation of the style and true stamens. 

 In the greater part of the order there is but one stamen present, and 

 it is in that case placed opposite the intermediate sepal, and consequently 

 alternate with the lateral petals : when, as in Cypripedium, there are 

 tw*o stamens present, then the usual stamen remains in its customary 

 position, in a sterile state ; and the two perfect stamens are additional, 

 and placed right and left of it It is supposed that in those species 

 which have but one anther there are two other stamens present in an 

 incomplete condition, and consolidated with the other; and from the 

 evidence offered by monstrous formations, it is thought that such 

 sterile stamens are represented in Orchis nod its allies by two tubercles, 

 oue on each side of the column ; hi Burling/onia by two auricles near 

 the apex of the column ; and by other signs in other cases. (Bauer, 

 'Illustrations of Orchidaceous Plants,' 4 to., London, 1830-1838, with 

 forty plates, in 4to.) 



In the greater part of the order a single anther terminates the 

 column. This is usually two-celled, but often has its cells divided 

 into two or four other cavities by the extension of the endothecium 

 between the lobes of the pollen masses, or is occasionally more or less 

 completely one-celled by the absorption of the connective. In Ophrydece 

 it is erect, with a distinct connective, and with the bases of the cells 

 either parallel or diverging, and then its cells dehisce along their face. 

 In Xcotticce it is also erect, but appears to be dorsal instead of terminal, 

 in consequence of the stigma being placed before it for its whole length. 

 In the remainder of the order it falls prone upon the head of the 

 column, or the clinandriutu, like a lid, and often is easily detached 

 times this kind of anther originates from the margin of the cliuan 

 drium ; sometimes from within the margin, in which case it is occasion 

 ally covered as by a hood, as in Cryptarrhena and other genera. 



The pollen consists of lenticular or spheroidal grains, either single 

 or cohering in pairs, threes, or fours, or in larger masses in indefinite 

 number. The grains are usually held together by an elastic filamentous 

 substance, which in all Ophrydece and many others forms an axis round 

 which the grains or masses of grains are arranged, and which in a very 

 large part of the order assumes the appearance of a strap or caudicula. 

 This body either contracts an adhesion with a gland originating on the 

 margin of the stigma, as in Ophrydece, Neottieoe, and Vandeie, or it is 

 folded upon the pollen masses, as in Epidendreae, or it terminates in 

 an amorphous dilatation, as in many Malaxirlea;. In all cases it con- 

 sists of cellular tissue, sometimes very lax and large, and thin-sided, as 

 in Potystachya ramulraa, more generally very compact, tough, and 

 thick-sided; towards the end, which adheres to the stigmatic gland, 

 the tissue becomes elongated, but otherwise it is more or less lenticular. 

 In Ophrydece the caudicula i extended towards the base of the anther- 

 cells ; but in all the other divisions of the order the caudicula, when 

 present, is lengthened in the direction of the apex of the cells. 



The differences in the structure of the column, anther, and pollen 

 now explained, furnish botanists with the best means of classifying 

 the order, and of breaking it up into sub-orders, in the following 

 manner : 



1. Malaridece (fig. 1), anther opercular; pollen waxy, with neither 

 caudicula nor gland. 



2. Kpidendreae (fg. 2), anther opercular; pollen waxy, with the 

 caudicula folded back upon the pollen grains, and no gland. 



3. Vandea (fy. 3), anther opercular; pollen waxy, with a mem- 

 brano-cartilaginous caudicula and gland. 



!AT. HIST. DIV. VOL. IV. 



4. Ophrydece (fig. 4), anther erect ; pollen sectile or granular. 



5. Aret/iusecs (fiy. 5), anther opercular ; pollen granular or powdery. 



6. Neottiete (fig. 6), anther dorsal ; pollen powdeiy. 



7. Cypripedieee, anthers two, separated by a broad sterile lobe. 



The ovary adheres firmly to the tube of the calyx, and is often so 

 twisted, when the flower is about to expand, that its back, with the 

 floral envelopes belonging to it, is turned to the front. It consists of 

 three perfect carpels, stationed alternately with the stamens opposite 

 the petals, and bearing the placenta; in their axis, and of three other 

 pieces alternate with the first, destitute of placentae, and eventually 

 separating from them when the fruit is ripe. 



The stigma is a viscid excavation in front of the anther, and just 

 below, it. In most cases it is quite simple, merely terminating in a 

 glandular dilatation of the upper margin, called the rostellum. It is 

 lined with a lax tissue composed of minute ascending jointed hairs, 

 and has a direct communication with the cavity of the ovary, either 

 open or only imperfectly closed up. The glandular dilatation in all 

 Vandea and Oiihrydenc, and in many geuera, separates from the stigma 

 and adheres to the pollen masses ; but it is also in numerous other 

 genera at all times inseparable from it. In Bonatea, in Habenaria, 

 and in some other genera of Ophrydece, there are two arms to the 

 upper edge of the stigma, each arm being channelled for the reception 

 of the caudicula of a pollen mass, and terminating in a separable 

 gland ; between these lies a membrane, very variable In size, some- 

 times merely a connecting web, sometimes a distinct plicature or lobe, 

 and occasionally fornicate, and extended in the middle into a nmcro. 



The fruit is usually a capsule of six valves, bursting when ripe, and 

 discharging a multitude of minute seeds, with a netted loose tunic. In 

 Vanilla however and some other genera the fruit is succulent, and the 

 seeds have a hard brittle integument immersed in aromatic pulp. The 

 eeeds apparently contain an exalbuminous embryo ; but from the great 

 minuteness of the parts this point is not yet satisfactorily determined. 



Impregnation in Orchidacece was at one time thought to take place 

 in a peculiar manner by the intussusception of the fertilising principle 

 of the pollen grains. It has now however been proved experimentally 

 by Brown, A. Brongniart, Morren, and the writer of this article, that 

 it in reality takes place only by the application of pollen grains to the 

 mucous surface of the stigma, as in other plants. 



This order contains 394 genera and about 3000 species. 

 The following genera, which are mostly described in this work under 

 their names, are British: Orchis, Gymnailenia, Aceras, Habenaria, 

 Ophryi, lierminium, Goodyera, Spiranthes, Liitera, Neotlia, Epipactis, 

 Cephalanthera, Corallorhiza, Malaxii, Sturmia, Cypripedium. 



(R. Brown, Prodromus Flora N. Hollandive, 8vo.,1810; the same 

 author, Observations upon the Jmpreynation of Orchideos and Asclepi- 

 adeoe, 8vo. ; Endlicher, Genera Planlarum, p. 185, 4to., Vienna; 

 Lindley, Genera and Species of Orchidaceous Plants, 8vo. ; Lindley, 

 Vegetable Kingdom.) 

 ORCHIDALES. [EHDOOENS.J 

 ORCHIL. [ROCCKLLA.] 



ORCHIS, a genus of Plants the type of the natural order Orchidacece, 

 and belonging to the tribe Ophiydincce. The old Linnsean genus Orchis 

 is now divided into many genera [OBCHIDACE.*:], but a large number 

 of species are still retained under this designation. The tribe Ophry- 

 dincte is distinguished by the pollen masses being divisible into lobes, 

 which are waxy and definite in number. The anthers are wholly 

 adnate. The genua Orchis belongs to a section of this tribe, in which 

 the cells of the anther have a rostellate process between their bases. 

 In Orchis the perianth is ringent and hooded ; the lip 3-lobed, spurred ; 

 the glands of the stalks of the pollen-masses are in a common pouch. 

 The following is an arrangement of the British species according to 

 Babington : 



* Glands of the pollen-masses separate ; lip erect in aestivation, 

 t Bracts mostly 1-nerved ; root-knobs undivided. 



Lip 3-lobed ; lobes broad and short. 



Orchis Mono, Green-Winged Meadow-Orchis. 0. maicula, Early 

 Purple Orchii. 



