WAYFARING NOTES IN RHODESIA 247 



selves, floating like miniature coracles. When stranded, they 

 maintain this position. In germination the seed cracks upon 

 the convex side, as may be seen in one of the specimens sent. 

 The reason for the float-apparatus appears to lie in the fact that the 

 rainy season has commenced by the time the seeds are ripe. The 

 local showers are very heavy and the surface of the ground may 

 be all awash for a time, in which case the seeds float off, are de- 

 posited in a suitable position for germination, and, at the same 

 time, secure a wider dispersal. One may find seeds of T. lanci- 

 folia around the plants at the beginning of the rains, but after 

 a few heavy showers they are washed away, and are diflicult 

 to find. 



SiLENE BuRCHELLii Bonth. (no. 1389). A shade plant, grow- 

 ing beneath trees upon the kopje. The stamens are divided, more 

 or less sharply, into two groups, five long and five short. The 

 anthers of the five long stamens dehisce near the mouth of the 

 floral tube, after which their filaments lengthen, lean aside, and 

 the anthers fall. The five short stamens now appear in the throat 

 of the tube, their anthers likewise dehisce and fall. Meanwhile 

 the three long stigmatic branches have been concealed within the 

 tube, erect, and in close apposition. After the second group of 

 stamens have shed their pollen, the stigmatic arms rise up out 

 of the tube and spread out widely beyond it in three feathery 

 stigmas. A protandry marked off into two stages seems note- 

 worthy. At their origin a long stamen regularly alternates with 

 a short one. The flowers are dull pink in colour, and close during 

 the heat of the day by a rolling inwards of the petals. 



Nes^a sp. (near N. linifoUa Hiern) (no. 1390). The stamens 

 are grouped, more or less completely, into two sets, a long and a 

 short. The two sets may be unequal as regards the number of 

 the component members. The style is well exserted, and leans to 

 one side of the flower, without variation in length. The habitat, 

 like that of Ltjthrum Salicaria, is in damp places. If the two 

 plants had a common ancestor, as seems probable, it is interesting 

 to see, how, with a like impulse to a division of the stamens, the 

 classical example has, in addition, a differentiation of its styles ; 

 whilst in Nescea, so far as the writer has observed, the style 

 remains a constant quantity. 



Ipom^a simplex Thunb. var. obtusisepala Rendle (no. 1391). 

 The withered stamens and petals, the latter thinned down into 

 membranes, enclose the fruit in its early stages as a thin, pro- 

 tective, papery envelope. 



Pterocarpus sp. (no. 1392). The fruits are ripening at the 

 end of December, and a tree in full fruit seen in slanting light 

 makes a striking picture, each wing a halo to the pod it encircles. 

 The trees are plentiful upon the kopje, where the ground is still 

 strewn with the last year's fruit, apparently little the worse for 

 wear. The hairs of the pod are probably defensive. In course of 

 time the longer bristles get broken off, when the pod wears the 



