10 

 THE ''AIR- plant:' DRYOPHYLLUM. 



An Interesting Plant of Hawaii. 



\^\UGHAN IMacCaughev, Thc College of Hazcoii. 



Hawaii can boast of many unique plants. There is perhaps 

 no region of similar area in the world whose flora is so rich in 

 peculiar forms. The "air-plant" or Bryophyllum, well-known 

 to many people, but unknown to a still greater number, is a plant, 

 found in these islands, that has many curious and remarkable 

 points of interest. 



The plants of the Hawaiian Islands may be grouped in two 

 great classes, — first, those that are native or endemic to these 

 islands ; and second, those that have been introduced through 

 human agencies. To the first class belong such plants as the 

 koa, kauila, maile, bird's-nest fern, etc. ; to the latter, such forms 

 as the taro, breadfruit, banana, sweet potato, and a host of other 

 useful and ornamental plants. 



The air-plant belongs to this latter group. It is of compara- 

 tively recent introduction, but has been rarried to several of the 

 islands. In Hawaii it is common in portions of the Kau lava 

 flows, and along the Kona road. On Oahu it occurs in abimd- 

 ance along the roadsides near the Nuuanu Pali. It forms a 

 conspicuous part of the undergrowth in the eucalyptus forest on 

 Tantalus, and. is found in various waste-places in the vicinity of 

 Honolulu (Fig. 1). It doubtless occurs on the other large islands 

 of the group. 



The special claim of the air-plant to our interest is its pecu- 

 liar ability to form new plants along the margins of its leaves 

 (Fig. 2). The leaves are arranged oppositely upon the stem, 

 and thus appear to be in pairs (Figs. 1, 4). This is a marked 

 contrast to the leaf-arrangement of such a jilant as hala (U' papaia, 

 whose leaves are arranged in spirals or whorls ; or that of sucii 

 plants as sugar cane or l)amboo, whose leaVes are arranged 

 alternately, each leaf being half-way arcnuid the stem from the 

 one immediately adjacent to it. 



'Ihe leaf itself is either sim])le in (Uitline, or is sonu'times 

 divided into several (usually three) large leaflets, the terminal 

 ftne being larger than thc otliers. The leaf is oval in shape, and 

 thick and fleshy in texture (Figs. 3, 4). Due to the .succulency 

 of the leaf its veins are indistinct, being more or less imbe<l;!ed 

 in thc fleshy tissues of the blade. A sliort, fleshy inliole at- 

 taches the leaf-blade to the stem. 



The margin of the leaf is scalloped or crenale, and it is from 

 these notches or serratir)ns that tlie little ])lants develoj). In 

 each notch on thc margin of a mature leaf there is a group of 



