90 STAMENS. 



Orchids, on the other hand, -.he number of pollen-sacs is reduced to two, a number 

 which remains unaltered at maturity. 



The pollen-sacs in the anthe-s of the Mimoseae are very curiousl}^ formed. In 

 the anthers of Acacia, Albizzia, (Jalliandra, and Inga, there are eight spherical 

 chambers in which pollen is producc^d, whilst in Parkia we find longitudinal rows 

 of lenticular cavities in which balls of pollen lie embedded. The anthers also 

 of the Rhizophoreffi show several long>,udinal rows of such chambers, amounting 

 in all to as many as thirty. The anthers of the Mistletoe {Viscum, fig. 214-') 

 contain as many as forty to fifty pollen-cha.nbers. In the majority of the Laurels 

 (Lauraceae) each anther is divided into four cavities, which stand in pairs, one 

 above the other. As a rule, all four open to^vards that side by which insects 

 visiting the flower for honey have to pass. 



Many marked variations in the form of the aither are due to the relative 

 dimensions of connective and pollen-sacs. Thus in the majority of Ranunculacese, 

 Magnoliaceae, Nymphfeaceae, and Papaveraceae, the con- 

 nective is broad, the pollen-sacs forming only a narrow 

 rim to the anther (c/. fig. 21 ti"). In the Skull-cap 

 {Scutellaria), Calamint (Calaminiha), Thyme (Thymus), 

 and many other Labiates, as als^ in several Rosacese 

 (Rosa, Agrimonia, &c.), the connecvive has the form of 

 a three- to six-sided mass of tissue in w^hich are embedded 

 Fig. 215. -Curved anthers In the the sphcrical or egg- shaped pollen-5:acs. Such anthers 

 SL^aVS B«. "'■ frequently resemble an insect's head with two lateral eyes. 

 It is not always possible to distinguish the limits of con- 

 nective and filament, the whole stamen resembling a truncate column or anvil 

 (figs. 216 -'^ and 216 =^-). 



Sometimes the connective assumes the form of a bar or lever running 

 transversely to the filament, to which it is attached by a movable joint. This 

 is notably the case in certain species of Salvia, to be described hereafter. Such 

 a connective moves very readily upon its fulcrum. In many Liliaceae (e.g. Tulips, 

 Lilies, and Crown Imperials) and several Gentians (Gentiana ciliata, nana, Szc), 

 the anther is united with the filament by an extremely delicate joint, so that 

 the slightest touch sets it in vibration (versatile anthers). As examples of bulky 

 pollen-sacs and much reduced connective, Mirahilis Jalapa (fig. 214 23) and Solarium 

 Lycopersicum (fig. 216^) may be quoted as examples. 



It stands to reason that the character of the anther, indeed of tlie whole stamen, 

 is correlated with the form of the pollen-sacs. All possible stag(3s occur between 

 globular and egg-shaped, and between egg-shaped and linear pollen-sacs. The 

 drawings of sixty-four different stamens in figs. 214 and 216 give a good idea 

 of the variety in this respect. Very curious are the curved anthers of Phyllanthus 

 Cyclantkera (fig. 215), and those of Acalypha, which resemble a ram's horns 

 (fig. 21426); ^jjQ same remark applies to the undulating anthers of many 

 Cucurbitaceae, of which those of Bryonia dioica may serve as an example 



