168 HETEROSTYLED TRIMORPHIC PLANTS. Chap. IV. 



above-described anther of the Lagerstrcemia ; we may there- 

 fore suspect that this species was once heterostyled, and 

 that it still retains traces of its former state, together with 

 a tendency to revert more completely to it. It deserves 

 notice, as bearing on the nature of Lagerstrcemia, that in 

 Lythrum hyssopifolia, which is a homostyled species, some 

 of the shorter stamens vary in being either present or 

 absent, and that these stamens are altogether absent in 

 L. thymifolia. In another genus of the Lythracese, namely 

 Cuphea, three species raised by me from seed certainly 

 were homostyled; nevertheless their stamens consisted of 

 two sets differing in length and in the colour and thickness 

 of their filaments, but not in the size or colour of their pol- 

 len-grains ; so that they thus far resembled the stamens of 

 Lagerstrcemia. I found that Cuphea purpurea was highly 

 fertile with its own pollen when artificially aided, but 

 sterile when insects were excluded.* 



Oxalis (Geraniace^). 



In 1863 Mr. Roland Trimen wrote to me from the 

 Cape of Good Hope that he had there found species of 

 Oxalis which presented three forms; and of these he 

 enclosed drawings and dried specimens. Of one species 

 he collected 43 flowers from distinct plants, and they 

 consisted of 10 long-styled, 12 mid-styled, and 21 

 short-styled. Of another species he collected 13 flowers, 

 consisting of 3 long-styled, 7 mid-styled, and 3 short- 



■ 



* Mr. Spence informs me that 

 in several species of the genus 

 Mollia (Tiliacese) which he col- 

 lected in South America, the 

 stamens of the five outer cohorts 

 have purplish filaments and green 

 pollen, whilst the stamens of the 

 five inner cohorts have yellow 

 pollen. He therefore suspected 

 that these species might prove to 

 be heterostyled and trimorphic : 

 but he did not notice the length of 

 the pistils. In the allied Luhea 

 the outer purplish stamens are 

 destitute of anthers. I procured 



some specimens of Mollia lepidota 

 and speciosa from Kew, but could 

 not make out that their pistils 

 differed in length in different 

 plants; and in all those which 

 I examined the stigma stood 

 close beneath the uppermost 

 anthers. The numerous stamens 

 are graduated in length, and the 

 pollen-grains from the longest and 

 shortest ones did not present any 

 marked difference in diameter. 

 Therefore these species do not ap- 

 pear to be heterostyled. 



