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Show 100 HETEROSrrYLED DIMORPHIC PLANTS. CHAP. III. short-styled plants of the two previous ~p.eci~s ap~arently evince some slight capacity for fertilisation with their own-form pollen, these three capsules may have been the product of self-fertilisation .. Besides the three species now descnbed, the yellowflowered L. coryrnbiferum is certainly heterostyled, as is, according to Planchon, * L. salsoloides: This botanist is the only one who seems to have Inferred that heterostylism might have some important functional bearing. Dr. Alefeld, who has 1nade a special study of the genus, sayst that about half of the sixtyfive species known to him are heterosty led. This is the case with L. trigynum, which differs so much from the other species th~t it has been forn1e<l by hin1 into a distinct genus. t According to the same author, none of the species which inhabit America and the Cape of Good Hope are heterostyled. I have examined only three homostyled species, namely, L. usitatissimum, angustifolium, and catharticum. I raised Ill plants of a variety of the first-named species, and these, when protected under a net, all produced plenty of seed. The flowers, according to H. Muller,§ are frequented by bees and moths. With respect to L. catharticum, the same author shows that the flowers are so constructed that they can freely fertilise themselves; but if visited by insects they might be cross-fertilised. He has, however, only once seen the flowers thus visited during the day ; but it * Hooker's ' London Journal of Botany,' 1848, vol. vii. p. 174. t 'Bot. Zeitung,' Sep. 18th, 1863, p. 281. t It is not improbable that the a1lied genus, Hugonia, is heterosty1f'( l, for one species is said by Planchon (Hooker's 'London Journal of Botany,' 1848, vol. vii. p. 525) to be provided with " staminibus exsertis ;'' another with ''sty lis staminibus longi~ribus' " and another has '' stam.m ,a 5, majora, sty los longe superant1a. § ' Die Befruchtung der Blumen,' &c., p. 168. CHAP. III. PULMONARIA. OFFIOINA.LIS. 101 may be suspected that they are frequented durinothe night by small moths for the sake of the fiv~ minute drops of nectar secreted. Lastly, L. Lewisii is. said by Planchon to bear on the same plant flowers with stamens and pistils of the same height, and others with the pistils either longer or shorter than the stamens. This case formerly appeared to me an extraordinary one; but I am now inclined to believe that it is one merely of great variability.* PULMONARIA (BORAGINElE). Pulmonaria officinalis.-Hilde brand has published t a full account of this heterostyled plant. The pistil of the long-styled form is twice as long as that of the short-styled; and the stamens differ in a corresponding, though converse, manner. There is no marked dif~ erence in the shape or state of surface of the stigma In the two forms. The pollen-grains of the shortsty led form are to those of the long-sty led as 9 to 7, or as 100 to 78, in length, and as 7 to 6 in breadth. They do not differ in the appearance of their contents. The corolla of the one form differs in shape from that of the other in nearly the same manner as in Primula; but besides this difference the flowers of the shortsty led are generally the larger of the two. Hildebrand collected on the Siebengebirge, ten wild longstyled and ten short-styled plants. The former bore 289 flowers, of which 186 (i.e. 64 per cent.) had set fruit, yielding 1·88 seed per fruit. The ten shortstyled plants bore 373 flowers, of which 262 (i.e. * Planchon, in Hooker's' Lond~ n Journal of Botany,' 1848, vol. vu. p. 175. See on this subject Asa Gray, in 'Americau Journal of Science,' vol. xxxvi. Sept. 1863, p. 284:. t ' Bot. Zeitung,' 1865, J a.n. 13, p. 13. |