Two Kinds of Stamens with Different Functions in 



the same Flower^). 



(Aus einem Briefe an Hermann Müller, dd. Blumenau, 13. Mai 1881.) 



Mit I Textfigur. 



The following extract from a letter lately received from my brother Fritz 

 Müller (of Blumenau, Prov. St. Catharina, Brazil) contains so new and curious an 

 Observation that it will probably interest the botanical readers of this Journal. 



"A species of Heeria (Melastomacese), which is not indigenous here, begins 

 in my garden now to open its beautiful red flowers, remarkable for having two 

 kinds of differently coloured anthers. The four petals spread in a perpendicular 

 plane ; the yellow anthers (a^) of the four shorter filaments, closely pressed together, 

 project from the middle of the flower; their bright yellow stri- 

 kingly contrasts with the violet-shining light red of the corolla ; 



Flower of Heeria spec, longitudinally dissected. s, sepals; p, petals; a', one 

 of the conspicuous yellow anthers which attract the insects; a^ one of the inconspicu- 

 ous red anthers, which powder the insects with pollen; c, connective of this anther; 

 /, fork of this connective ; st, stigraa. 



the longer anthers (a^) are red, like the filaments, and the very long connective 

 (c), which is lengthened beyond the point of insertion into a fork (/), with 

 two yellowish points; these points stand close beneath the yellow anthers. 

 whilst the apical apertures of the red anthers (a-) are placed far below them 

 near the stigma ; also the style and the stigma {st) are coloured so very hke the 

 corolla, that from some distance neither they nor the longer stamens can be 

 Seen at all. Any large bee (like Xylocopa, Centris, or Bombus), when working 

 on the smaller anthers in order to collect pollen, would, by moving the connec- 

 tive fork of the larger ones, press the apertures of the latter against the ven- 

 tral side of its abdomen and powder it with pollen. Until now I have only 

 seen a little fly (Syrphidae) and Trigona riificrus visiting this flower, both too 

 small to fertilise it. The fly takes only notice of the yellow anthers ; the Trigonas, 

 too, always sit down first on these; but most of them (the more experienced 

 specimens ?) turn then round, and go to the larger anthers, which offer a more 

 copious poUen-store, and work on them with their mandibles or eat them up en- 

 tirely. Even if larger bees acted in the same manner as Trigona riificrus, 

 they would have powdered the ventral side of theyr abdomen before going to 

 plunder the latter. The pollen of both kinds of anthers is white." 



I) Natura 1881. Bd. XXIV. p. 307. 



