172 



HARDWICKE'S SCIENCE-GOSSIP. 



[Aug. 1, 1868. 



known as P. depressa, is the commoner species ; it 

 has weak prostrate stems, small, frequently opposite 

 leaves, and small flowers. The latter, the true 

 P. vulgaris, is a much stouter plant, with ascending 

 stems, larger and longer leaves, and handsomer, 

 more brilliant blossoms. In some places, as on the 

 chalky slopes near 1 Hughenden, its bright pink or 

 blue blossoms contrast beautifully with the orange 

 chaplets of the Horseshoe Vetch {Hippocrepis 

 cotnosa). We have remarked that white-flowered 

 examples, which are common enough in P. depressa, 

 are rarely seen in P. vulgaris. 



Fig. 166. Habenaria chlorantha. 



In the Pea and Bean Tribe {Leguminosce), the 

 pretty Restharrow gives us two well-defined forms, 

 neither of them uncommon, although the two are 

 not often found together. The Thornless Rest- 

 harrow {Ononis arvensis) is a soft plant, the leaves 

 and stem being covered with clammy hairs, and the 

 former almost, if not quite, without thorns. In the 

 Thorny Restharrow (0. campestris) the stem is very 

 thorny, the leaves and blossoms are smaller, and 

 without the clammy hairs of 0. arvensis. 0. arvensis 

 frequents the borders of fields and hedge-banks, 

 while 0. campestris prefers dry open places, such as 

 Wandsworth Common, Surrey. Remembering this 

 difference of locality, one might almost be inebned 

 to fancy that these variations might be caused by 

 situation alone, especially as we know that thorns 

 are really only abortive leaf-buds. But the pods of 

 0. arvensis fall short of the calyx, while those of 

 0. campestris exceed it ; so that we may readily 

 discriminate between the two. We have never 

 been able to find the Thorny Restharrow in our 

 Wycombe district, although we have received a 



specimen from the north of the county but the 

 Thornless Restharrow is very general here, and 

 we have once found it with a few weak thorns upon 

 the stem, — very different, however, to those of 

 0. campestris. A variety {parviflorum) of the Purple 

 Clover {Trifolium pratense) may be noticed in dry 

 places ; it has stalked flower-heads, and the calyces 

 equal, or exceed, the corolla in length. 



Fig. 16". Side view of flower of Habenaria chlorantha. 



The Wild Valerian {Valeriana officinalis) is divided 

 in Babington's "Manual" into two species, which 

 are said to require more study. The differences 

 between them seem slight : the form retaining the 

 name V. officinalis having " suckers, not stoles ;" 



Fig. 168. Side view of flower of Habenaria bifulia. 



while the second, V. sambucifolia , has "long 

 stoles." To understand this distinction, we must 

 remember that a stole is defined as "a long trailing 

 shoot from the crown of the root, rooting at in- 

 tervals," of which we And a good example in the 

 Sweet Violet {Viola odorata) ; while a sucker is 

 " a stem produced at the end of an underground 

 shoot," as in the Great Willow-herb {Epilohium Mr- 

 sutum). Eorcign authors lay stress upon the number 



