. The classification of flowering plants. Plants. V] ORCHIDACEAE 363 The nature and arrangement of the adhesive mechanism was considered of prime importance by the older botanists in the subdivision of the Order. The great tribes recognised by Lindley* are characterised by differences in the pollinia and the means adopted for their transmission. In the tribe Ophrydeae, which includes our native genera Orchis (fig. 175), Ophrys, and Gymnadenia, the anther is attached to the rostellum by its base (whence the group-name basitonae), where it is produced into two longer or shorter processes, the co
. The classification of flowering plants. Plants. V] ORCHIDACEAE 363 The nature and arrangement of the adhesive mechanism was considered of prime importance by the older botanists in the subdivision of the Order. The great tribes recognised by Lindley* are characterised by differences in the pollinia and the means adopted for their transmission. In the tribe Ophrydeae, which includes our native genera Orchis (fig. 175), Ophrys, and Gymnadenia, the anther is attached to the rostellum by its base (whence the group-name basitonae), where it is produced into two longer or shorter processes, the contents of which include only a few pollen-grains and become hardened to form the stalk-like caudicles. The caudicles are attached above to the numerous packets of grains forming the. Fig. 175. AâD. Orchis mascula (Purple Orchis). A. Front view of anther and top of column; a, anther; s, s, pair of stigmatic surfaces, one on each side of the rostellum, r. The pollen-sacs have split lengthwise, exposing the pollinia in the upper portion. On either side of the anther is a blunt outgrowth representing a sterile stamen. B. Dissection of flower, side view, shewing part of lip and the spur {sp) and the relation of rostellum (?â ) and stigma (s) to entrance of spur. C. Base of pair of pollinia, front view; c, caudicles; r, rostellum ; g, gland ; m, membranous disc. D. Single pollinium, the pollen-containing portion separated, shewing arrangement of packets of pollen on the two main axes. E. Pollinia of O. pijramidaUs attached to a common gland (g). All enlarged. A, D, from original drawing by Fr. Bauer. B, C, E, after Darwin. pollinia, and below to the rostellum, in which originate one or two sticky masses (the so-called glands) formed by disorganisa- tion of the tissue. The position of the rostellum in relation to the entrance to the spur or corresponding portion of the flower which is probed by the insect is such that in leaving the flower the visitor carries away the gland (fig. 17
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