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A TEXTBOOK OF THEORETICAL BOTANY 



stantly produced as part of the sequence, as in Trollius and Nyrnphaea, 

 forming an intergrade zone between completely sterile petals and completely 

 fertile stamens. 



Fig. 1 166. — Undifferentiated stamens in Chloranthaceae. 

 A, Sarcandra glaber. B, .S. hairanemis, both with 

 branching vascular supply. C, Chloranthus officinalis. 

 Three lobed stamen with three trace bundles and eight 

 pollen-sacs. Sarcandra is devoid of vessels in the wood. 

 {After Snamy and Bailey.) 



There are a few instances of expanded stamens apart from true peta- 

 lody. The uppermost stamens in Aquilegia vulgaris are changed into a circle 

 of six elongated scales surrounding the carpels. They sometimes show their 

 character by producing imperfect anthers. The Tree Paeony {Paeonia 

 moutan) also has a scaly envelope surrounding the carpels, which is irre- 

 gularly toothed and may be an upgrowth of the receptacle, but seems more 

 probably to be derived from the uppermost stamens, as it sometimes bears 

 anthers. 



The sensitive stamens of Berberis and Centaiirea will be dealt with below, 

 under stamen anatomy. See p. 1196. 



Staminal stipules are not uncommon and either take the form of scales 

 or outgrowths or, frequently, glands. The stipules in the form of scales 

 are either attached on each side of the filaments or united to each other, 

 either adaxially or abaxially, across the filament, in a manner corresponding 

 to that in which foliar stipules may become united across the petiole. 

 Examples are to be found in many families, notably the Chenopodiaceae, 

 Amarantaceae, Meliaceae and, among Monocotyledons, where foliar stipules 

 are scarce, in several species of Allium. The Simarubaceae (the Ailanthus 

 family) have remarkably developed staminal stipules. In Simaba, they are 

 united tangentially into an elongated tube on which the stamens are borne 

 aloft. It might be mistaken for a tubular corolla with epipetalous stamens. 

 The Lauraceae are notable for the paired lateral appendages which nearly 

 all its members produce at the base of the filaments (Fig. 1163). They are 

 often glandular but are stipular in nature and are practically a diagnostic 

 character of the family. Ligulate stamens also occur, e.g., in Alyssum 

 montanum where the ligule, attached to the adaxial face of the filament, is 

 long on the short stamens and vice versa. In Melastomaceae the ligule is 

 extraordinarily developed and protrudes from the filament in a curve, above 

 which the filament is often sharply bent outwards. 



The term staminode is applied to sterile and usually reduced stamens, 



