AVTOOAMT BY THE BEXriXC, OF THE FISTIL 353 



jible. Thus, dichogamy, iuvohiiii: haixily half-an-hour's interval betvreen the 

 attainment of maturity in stigmas and anthei-s respootively, is sufficient to ensm-e 

 cross-fertiHz{\tiou at the commeucemeut of the period of bloom in each flower of 

 this kind of uight-flowering plant. A ftu-ther adaptation with a view to hetero- 

 ipinv is shown in the position of the stigma in fixtut of the anther in the first stage 

 of tloral development i^see tig. i!90 ■''"). On the inti-usion of insects — Spliingid;^. 

 Xc>otu:¥, v'cc. — into the interior of the flower the large stigma is the fii-st object 

 encouutei-ed. and next to it come the anthei-s, and there is therefore a possibility 

 that even d\iring the time that the anthei-s are open and have their pollen exposed 

 CKvi^-fertilization may take place thixingh the agency of insects. If, however, no 

 insects^ visit the flower the style bends down the very next morning in an open 

 curve and lays the stigma tiat upon the anthei^ v*^'? t^g^- -i^i^*). The pollen readily 

 adheres to the surface of the stigma, as may be seen by removing that oriran after 

 it has become appressed to the anthei-s, when a thick layer of pollen will be found 

 snckintr to it (^fig. -00 "''l 



Inflections of the style in all respects similar to those exhibited in Morina occur 

 in the flowers of mimei-ous Ehinanthace^, e.g. in Shinanthus minor, TriMigo 

 apula. M{\xmv;jvmn pnxtensi. Euphi-a^'ia minima (see tigs. 299^ and 209 "Y In 

 these plMits we find, in general, a repetition of the entii-e pi-ocess above described. 

 except for the cireumstance that the pollen is not adhesive but mealy, and is not 

 transferred to the receptive tissue by appression of the stigma to the anthers — it 

 being sufficient to place the stigma luider the anthers by means of an inflection of 

 the style. The stamens in this case are of the sug-ar-toug-s type {cj. p. 271\ In 

 the first and second stages of floral development the mealy pollen only falls oiit of 

 the anthers on the occasions when the stili" filaments of the stamens ar^e forced aput 

 by insects. Should no insects visit the flower the pollen remains in the locttli. In 

 the third stage of flowering the filaments become flaccid, as does ;\lso the portion of 

 the corolla adjacent to them, and in consequence the anthei-s. which have hitherto 

 been closely coherent, move a Httle apart fivm one another and let the pollen fall 

 Ottu Meanwhile the style has bent down sufficiently to bring the viscid stigma 

 tmder the front pair of anthei'S, so that a portion of the pollen is canght upon its 

 glistening surface, with the result that autog-;imy is efiected v*<?<? fig- -00 '\ It is 

 not uncommon for the inflection of the iipper thirel of the style to be so STre">ng as 

 toamovmt to an invohition, and the stigma is then pushed between the disuniting 

 anthers and comes into contact with the hairs which clothe the anthei-s. and which 

 are usually powdered all over with pollen. 



Iriiyrus. ^Ic ina, and the Ehinanthacefe jnst mentioned, are all protogynons. 

 whilst on the other hand, the Evening-primrose, Willow-herb, Campion, and Mal- 

 low, in which autog-amy likewise occtu-s in consequence of the style landing down 

 to the anthers, are protandrous. "'rt'hen the petals of the Evening-primrese {CErio- 

 '">fm biamis. CE. muricafa. kc.\ or of the lai-ge-flowered species of Willow-herb 

 (EpihAium hirfutum,£. angufrifolium, see fig. oOCi expand, the fotu- branches of 

 the style, which bear the receptive tissue and constitute the sti^uias. are closely 



