132 



HENDERSON'S HANDBOOK OF PLANTS 



DOT 



A genus of tropical herbaceous Ferns, allied 

 to Pteris. Some of the species are now includ- 

 ed under the latter genus. They are common 

 in South America and the East and West 

 Indies. Propagated by spores. 



Dotted. Furnished with transparent recep- 

 tacles of oil, looking like dots ; marked with 

 punctures. 



Double. When applied to the entire flower, it 

 signifies that monstrous condition in which 

 the parts of the inner floral whorls, the sta- 

 mens or carpels, become converted into petals. 

 Applied to the calyx or corolla separately, it 

 refers to certain examples in which these 

 organs appear to consist of more than the 

 usual normal number of subordinate parts, 

 and thus seem as if they were double. Double 

 flowers are most common in the natural order 

 Composite. 



Dougla'sia. A very pretty genus of herba- 

 ceous plants from the Eocky Mountains, 

 and Artie North America, of the Nat. Ord. 

 Primulacece. 



The plants are evergreen, and like many 

 others from high latitudes, will not bear sud- 

 den changes ; consequently they need protec- 

 tion in winter. The flowers are small, of a 

 beautiful purple, borne in small tufts. This 

 genus was named by Dr. Lindley in compli- 

 ment to David Douglas, whose zeal in collect- 

 ing seeds and plants, and whose untimely end 

 have richly earned for him a niche in the long 

 gallery of 'departed martyrs to science. Mr. 

 Douglas was borne in Scone, Scotland, in 1798, 

 and killed in the Sandwich Islands, July 12th, 

 1834. Having been employed in the Glasgow 

 Botanic Garden, his intelligence attracted the 

 notice of Sir William Hooker, who procured 

 for him an appointment as botanical collector 

 to the Horticultural Society of London. In 

 this capacity he traveled extensively in 

 America. In 1824 he explored the Columbia 

 River and California, and in 1827 traversed 

 the continent from Fort Vancouver to Hud- 

 son's Bay, where he met Sir John Franklin, 

 and returned with him to England. He made 

 a second visit to the Columbia in 1829, and after- 

 wards went to the Sandwich Islands. His 

 death was caused by falling into a pit made to 

 entrap wild cattle, where he was killed and 

 mutilated by an animal previously entrapped. 

 Through his agency 217 new species of plants 

 were introduced into England. He collected 

 800 specimens of the California Flora. A gigan- 

 tic species of Pine which he discovered in Cal- 

 ifornia is named after him, Abies or Paeudo- 

 tsuga Douglasii. 



Doum Palm. See Hyphcene. 



Dove Flower. See Peristeria elata. 

 Waxen. Peristeria cerina. 



Down Thistle. Ornopordon Acanthium. 

 Down Tree. Ochroma Lagopus. 



Downi'ngia. Named in honor of A. J. Downing, 

 the father of horticulture in the United States. 

 Nat. Ord. Lobeliacece. 



A genus of hardy annuals from California 

 and British Columbia, free flowering, and very 

 pretty for the border. If the seeds be sown in 

 February, and the plants treated the same as 

 Verbenas, they will flower by the first of 

 June and continue until killed by frost. The 

 flowers are of lovely blue, not unlike the 



DRA 



Lobelias. Introduced by Mr. Douglas in 1827. 

 These plants have erroneously been called 

 Clintonia, which name properly belongs to a 

 genus of LiliacecB. 



Dra'ba. Whitlow-Grass. From drabe, acrid; 

 referring to one of the universal characters of 

 its natural order. Nat. Ord. Cruciferce. 



A genus of hardy rock or alpine plants, con- 

 sisting of annuals, biennials and herbaceous 

 perennials. They are very low plants, admira- 

 bly adapted for rock-work, as they are gen- 

 erally found in a wild state in the fissures 

 and crevices of rocks and mountains. They 

 have white or yellow flowers, and should be 

 grown with good drainage and a sunny 

 exposure. Propagated by root division, or 

 by seeds. First introduced in 1731. 



Dracae'na. From drakaina, a female dragon ; 

 the thickened juice becomes a powder, like 

 the dragon's-blood. Nat. Ord. Liliacece. 



Dracaenas rank among the most beautiful 

 and useful of the ornamental-foliaged and 

 fine-leaved plants. In a large or small state 

 they are alike elegant and attractive. They 

 are deservedly popular for the green-house or 

 the sub-tropical garden, and for lawn decora- 

 tion, large plants of many of the species have 

 no equal. The species include the celebrated 

 Dragon-tree (D. Draco) at Orotavia, in the 

 island of Teneriffe, that was first noticed by 

 Humboldt, who estimated its age at 6,000 

 years. This tree was seventy feet in height 

 and seventy-nine feet in circumference at the 

 base. The interior of the trunk, which had 

 been hollow for centuries, was used as a, 

 Roman Catholic chapel after the conquest of 

 the island by the Spaniards. Unfortunately 

 it was totally destroyed by a hurricane which 

 occurred in 1867. D. terminal-is (or more cor- 

 rectly Cordyline), a native of both the East and 

 West Indies, is the best known of the species, 

 and is extensively grown for baskets, window 

 gardens, or the conservatory, the vivid coloring 

 of its leaves rendering it at all times attract- 

 ive. From this species has originated the 

 host of popular hot-house varieties, many of 

 which are most desirable and interesting 

 because of their varied and rich tints of color, 

 and their gracefully recurved foliage. Nearly 

 all the species are admirably adapted for 

 decorative purposes. D. Goldieana is a mag- 

 nificent stove-house species, introduced from 

 tropical Africa in 1872. Its broad, deep green, 

 spreading leaves are marbled and irregularly 

 banded with silvery-gray in alternate straight 

 or furcate bands, rendering it one of the most 

 striking and ornamental of the genus. D. 

 umbraculifera, introduced from the Mauritius 

 in 1778, is a very peculiar and distinct species, 

 with long, narrow, dark green leaves, very 

 closely set, and horizontal, with the ends 

 slightly recurved, giving it the appearance of 

 a table top or umbrella. For the sub-tropical 

 garden or for the lawn, D. indivisa and D. 

 Australia, Syn. Cordyline, are the best, being of 

 graceful habit, rapid growth, and not affected 

 by sunshine, storm or drought. They are 

 natives of New Zealand, and are readily 

 increased from seed. The other species are 

 propagated by placing the stems on the prop- 

 agating bench in sand, with a bottom heat of 

 75, and slightly covering them with sphag- 

 num, which should be kept at all times moist; 

 in a short time an eye will break forth from 



