HALORAGE.E — LYTHRARIE^ 



191 



HiPPURIS 



The minute flowers are ^Yitllout petals. The leaves 

 are entire. 



H. vulgaris (Mare's Tail). — Grenier and Godron 

 mention ^ a specimen in which the leaves were arranged 

 spirally instead of in whorls. 



LYTHEAEIE^ 



Lythrum 



We have two British species — L. Salicaria, with 

 upright stems and reddish-purple flowers ; and L. 

 hyssopifolia, small and decumbent, with minute petals. 



L. Salicaria has three distinct forms of flower, 

 which were already recorded by 

 Vaucher, while their functions and 

 relations were first explained by 

 Darwin. He distinguished them 

 according to the length of their style, 

 as long-styled (Fig. 135), mid-styled 

 (Fig. 13G), and short-styled (Fig. 

 137). In this species it is remark- 

 able that the seeds of the three forms 

 diff'er from one another, 100 of the 

 long-styled seeds being equal to 121 

 mid-styled or 142 short -styled. The 

 pollen grains also not only differ in 

 size, the long stamens having the 

 largest pollen grains, the middle- 

 sized stamens middle - sized pollen 

 grains, and the short stamens small fig. 134. —inflorescence 

 pollen grains, but also in colour, being te^^i^" ^"""''"''' 

 green in the longer stamens and yellow 

 in the shorter ones, while the filaments are pink in the 

 long stamens, uncoloured in the shorter ones. Darwin 



^ Flore de France, vol. i. 



