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Show 324 CLEISTOGAMIC FLOWERS. CHAP. VIII. flowers of the double violet have been rendered double. Vandellia nummularifolia.-Dr. Kuhn has collected* all the notices with respect to cleistogamic flowers in this genus, and has described from dried specimens those produced by an Abyssinian species. Mr. Scott sent me from Calcutta seeds of the above common Indian weed, from which many plants were successively raised during several years. The cleistogamic flowers are very small, being when fully mature under do of an inch (1· 27 mm.) in length. The calyx does not open~ and within it the delicate transparent corolla remains closely folded over the ovari urn. There are only two anthers instead of the normal number of four, and their filaments adhere to the corolla. The .. cells of the anthers diverge much at their lower ends and are only 7%0 of an inch ( ·181 mm.) in their longer diameter. They contain but few pollen-grains, and these emit their tubes whilst still within the anther. The pistil is very short, and is surmounted by a bilobed stigma. As the ovary grows the two anthers together with the shrivelled corolla, all attached by the dried pollen· tubes to the stigma, are torn off and carried upwards in the shape of a littl~ cap. The perfect flowers gene· rally appear before the cleistogamic, but sometimes simultaneously with them. During one season a large number of plants produced no perfe~t flowers. It has been asserted that the latter never yield capsules; but this is a mistake, as they do so even when insects are excluded. Fifteen capsules from cleistoga1nic flowers on plants growing under favourable conditions con· tained on an average 64· 2 seeds, with a maximum of 87 ; whilst 20 capsules from plants growing much * ' Bot. Zeitung,' 1867, p. 65. CHAP. VIII. ONONIS. 325 cro1w df:e d yielded an avera()'e of onl 48 s· t b Y . IX con cap-su es rom perfect flowers artificially cross d with pollen fr?m anoth~r plant contained on an averao-e 93 se d wit~ ~ maximum of 137. ~rhirtecn capsul~s from s lf~ fertilised perfect flowers gave an averao·e of 62 d 'th · b see s, WI a ~aximu~ of 135. Therefore the capsules from the cleistogamic flowers contained fewer seeds than those from perfect flowers when cross-fertilised 1 sr I g h t 1y more t h an those from perfect flowe . ' anlfc' e .1. d rs se - 1ert1 Ise . Dr. Kuh~ believes that the Abyssinian V. sessijlora does .not dr~fer spe~ifically from the foregoing species. But Its. cleistogamic flowers apparently include four anthers Instead of two as above described. The plants moreover, of V. sessijlora produce subterranean ' h. h . ld runners w Ic YI~ capsules; and I never saw a trace of such runners 1_n V. nummularijolia, although many lants were cultivated. p L. inda rbia spuria.-Michalet says* that sho r t , thI' n, tw~ste ranches are developed from the buds in the axils o~ the lower leaves, and that these bury themselves In. the ground. They there produce flowers not offering any peculiarity in structure excepting that their corollas, though properly colou;ed, are de· formed. These flowers may be ranked as cleistogamic as they are developed, and not merely drawn, beneath the ground. · Ononis columnm.-Plants were raised from seeds sent me ~rom Northern Italy. The sepals of the cleistogamic flowers are elongated and closely pressed tofether ; ·the petals are much reduced in size, colour-ess, and folded over the interior organs. The filaments of the ten stamens are united into a tube, and * ' Bull. Soc. Bot, de France,' tom. vii. 1860, p. 468. |