Petalidium

Petalidium rautanenii, copyright Erin Tripp.

Belongs within: Acanthoideae.

Petalidium, petal-bushes, is a genus of shrubs found in drier regions of Africa and India.

Characters (from Flora of Tropical Africa): Small, shrubby. Leaves entire. Pedicels to flowers very short; inflorescence of contracted monopodial cymes, often reduced to single flowers, of which many branches are often sterile and carrying linear (often long ciliate) bracts. Bract small, narrow, or absent; bracteoles large, ovate or elliptic, concave, enclosing calyx, ultimately more or less scarious and reticulately veined. Calyx small; segments lanceolate or linear, 2 anticous connate 1/4 their length or nearly to the tip. Corolla usually small; tube straight or curved, dilated in upper half or only funnel-shaped at very top; segments 5, contorted in bud, usually nearly equal, two-lipped or not. Stamens 4, subsimilar; filaments nearly glabrous except at the base; anther-cells parallel, subequal, base short-tailed apiculate or muticous; pollen ellipsoid, longitudinally few ribbed, stopples 3, with (nearly always) 1 tubercle above and below each stopple. Style thinly hairy; stigmatic arms linear-oblong, subequal or unequal, rarely one obsolete. Ovary with 2 ovules in each cell, glabrous. Capsule small, commonly 1/4 inch long, sessile, ovate or ellipsoid, compressed, hard, brown, shining, woody throughout, placentæ with seeds rising elastically from the base of the capsule. Seeds 4 or more often 2, with numerous hygroscopic hairs.

<==Petalidium [incl. Pseudobarleria] SV00
    |--P. canescens CV06
    |--P. cymbiforme CV06
    |--P. giessii CV06
    |--P. glandulosum SV00
    |--P. lanatum CV06
    |--P. linifolium CV06
    |--P. luteo-album CV06
    |--P. ohopohense CV06
    |--P. pilosi-bracteolatum CV06
    |--P. ramulosum CV06
    |--P. rautanenii CV06
    `--P. subcrispum CV06

*Type species of generic name indicated

REFERENCES

[CV06] Craven, P., & P. Vorster. 2006. Patterns of plant diversity and endemism in Namibia. Bothalia 36 (2): 175–189.

[SV00] Scotland, R. W., & K. Vollesen. 2000. Classification of Acanthaceae. Kew Bulletin 55 (3): 513–589.