38o 



A TEXT-BOOK OF BOTANY 



Fig. 221. Different types of stamens. Abbreviations: filament (f), pollen sacs or 

 iheca (sporangia) (th), connective (c). A, stamens of a water lily {Nymphcea) showing 

 variation in the stamens (a-d) ; B, theca near middle of the stamen of Popowia; C, anther of 

 another species of Popowia with fleshy connective and pollen sacs on either side; D, stamen 

 of Tradescantia with transverse connective; E, F, G, stamens of several Commelinacece 

 with broad connectives; H, stamen of Salvia with peculiar swinging connective and an 

 aborted pollen sac or staminodium (std) at the lower end and the fertile pollen sac above; 

 J, peculiar elongated connective of Unona; K, elongated connective of Humiri; L, androe- 

 cium of violet showing two spurred sessile stamens; M, stamen of Columelia with sinuous 

 confluent anthers, broad connective and short filament; N, confluent transverse pollen 

 sacs of .4 mar Mm; O, united pollen sacs of Columbine showing small connective; P, spherical 

 pollen sacs of Ca//a, with slightly developed connective; Q, versatile anther and long, slen- 

 der filament of dead nettle {Lamium album); R, dehiscence of anther of Solanum by means 

 of terminal pores; S, spurred anther of Arbutus with terminal pores; various kinds of val- 

 vular dehiscence, as in Berberis (T), Atkerosperma (U) and Persea (V). — A, after Caspary; 

 B. H-R, U, V, after Baillon; S. T. after Sachs; D-G, after Schonland. 



to be EXTRORSE, as in the ^lagnoliaceae ; when they lie horizontally 

 on the tip of the filament, so that they swing as on a pivot, as in 

 the tiger lily, they are said to be versatile ; when they adhere 



